Full Changelog

Version 6.0.dev728+g0c73d13 (2023-09-26)

New Features

astropy.coordinates

• Support has been added to create geodetic representations not just for existing ellipsoids from ERFA, but also with explicitly provided values, by defining a subclass of BaseGeodeticRepresentation with the equatorial radius and flattening assigned to _equatorial_radius and _flattening attributes. [#14763]

• Add BaseBodycentricRepresentation, a new spheroidal representation for bodycentric latitudes and longitudes. [#14851]

astropy.cosmology

• Added a write_latex() method for exporting a Cosmology object to a LaTex table. [#14701]

• Added argument rename to Cosmology’s I/O, allowing for input and output symbols to be renamed. [#14780]

• All non-abstract Cosmology subclasses are now automatically registered to work with Astropy’s YAML serialization. [#14979]

• Cosmology I/O now auto-identifies the ‘.tex’ suffix with the ‘ascii.latex’ format. [#15088]

astropy.table

• The new Row.get() method, analogous to dict.get(), returns the value of the specified column from the row if the column present, otherwise it returns a fallback value, which by default is None. [#14878]

astropy.uncertainty

• Uncertainty Distribution now support structured data types, and as a result it now works also with EarthLocation. [#15304]

astropy.units

• Add support for gc2gde and gd2gce erfa functions to allow geodetic representations using equatorial radius and flattening. [#14729]

astropy.utils

• The astropy.utils.metadata.MetaData default dictionary can now be set with the default_factory keyword argument. [#15265]

• astropy.utils.decorators.deprecated now adds the __deprecated__ attribute to the objects it wraps, following the practice in https://peps.python.org/pep-0702/. [#15310]

astropy.visualization

• Add WCSAxes.text_coord method to print text using SkyCoord objects parallel to plotting data points with WCSAxes.plot_coord. [#14661]

astropy.wcs

• Support WCS descriptions of basic planetary coordinate frames. [#14820]

• Updated bundled WCSLIB version to 8.1. This update adds support planetary keywords A_RADIUS, B_RADIUS, C_RADIUS, BLON_OBS, BLAT_OBS, and BDIS_OBS in auxprm and adds wcsprm::time to the wcsprm struct to record the TIME axis. This update also includes several bug fixes. For a full list of changes - see http://www.atnf.csiro.au/people/mcalabre/WCS/CHANGES [#15035]

API Changes

astropy.convolution

• Invalid kernel arithmetic operations now raise a KernelArithmeticError instead of a bare Exception. [#14728]

• Added base KernelError error class and removed DiscretizationError error class (a ValueError will be raised instead). [#14732]

• discretize_model will now raise a ValueError if mode='oversample' and factor does not have an integer value. [#14794]

astropy.coordinates

• Removed deprecated angle parsing and formatting utilities from angle_utilities. Use the functions from angle_formats instead. [#14675]

• The deprecated functionality of initializing Angle or Longitude from a tuple is no longer supported. [#15205]

• Angle-related classes and functions have been moved within astropy.coordinates. There is no change to public API as everything moved should still be imported from astropy.coordinates, not a sub-module. If you are using private API, try importing from astropy.coordinates instead. If you need something that has been moved and is not available in astropy.coordinates, please open an issue on the Astropy issue tracker. [#15220]

astropy.cosmology

• Removed support of importing private constants and functions from astropy.cosmology.flrw. [#14672]

• Removed deprecated Cosmology Parameter argument fmt. [#14673]

• Removed deprecated vectorize_if_needed and inf_like from cosmology.utils. [#14677]

• Removed deprecated import paths from astropy.cosmology.core. [#14782]

• Cosmology Parameter is now a dataclass, and can work with all of Python’s dataclasses machinery, like field introspection and type conversion. [#14874]

• A new property – scale_factor0 – has been added to Cosmology objects. This is the scale factor at redshift 0, and is defined to be 1.0. [#14931]

• Added registration label ascii.latex to Cosmology IO. [#14938]

• The private module astropy.cosmology.utils has been deprecated. [#14980]

astropy.io.misc

• Removed deprecated astropy.io.misc.asdf subpackage. Use asdf-astropy package instead. [#14668]

astropy.io.votable

• Removed deprecated pedantic option from the astropy.io.votable.table.parse() function and the corresponding configuration setting. Use the verify option instead. [#14669]

astropy.modeling

• Removed the AliasDict class from modeling.utils. [#12943]

• Creating a model instance with parameters that have incompatible shapes will now raise a ValueError rather than an IncompatibleShapeError. [#15209]

astropy.tests

• Removed deprecated deprecation, warning, and exception handling functionality provided by astropy.tests.helper. [#14670]

• astropy.tests.command.FixRemoteDataOption and astropy.tests.command.AstropyTest are deprecated. They are no longer necessary after sunsetting astropy-helpers. [#15204]

astropy.uncertainty

• The .dtype attribute exposed by Distribution is now that of the samples, rather than one that has a “samples” entry. This makes quantities with structured data types and units easier to support, and generally makes the Distribution appear more similar to regular arrays. It should have little effect on code. For instance, distribution["samples"] still will return the actual distribution.

  As a consequence of this refactoring, most arrays that are not C-contiguous can now be viewed and will thus not be copied on input any more. The only exceptions are arrays for which the strides are negative.

  Note that the true data type is considered an implementation detail. But for reference, it now is a structured data type with a single field, “samples”, which itself is an array of “sample” fields, which contain the actual data. [#15304]

astropy.units

• Like np.ndarray, under numpy 2.0 Quantity and all its subclasses (Angle, Masked, etc.) will no longer support the .ptp() method. Use np.ptp(...) instead.

  Similarly, support for the much less frequently used .newbyteorder() and .itemset() methods has been removed. [#15378]

astropy.utils

• Removed deprecated OrderedDescriptor, OrderedDescriptorContainer, and set_locale in astropy.utils.misc. [#14679]

• is_path_hidden() and walk_skip_hidden() are deprecated. [#14759]

• The structure of utils.metadata has been refactored, but all the available functions and classes are still present and should be imported as before. [#15166]

• The astropy.utils.metadata.MetaData class, which is used throughout astropy to carry metadata on tables, columns, etc., can now also be used on dataclasses.

  When accessing the meta attribute on a class astropy.utils.metadata.MetaData now returns None instead of itself. [#15237]

astropy.visualization

• It is now not possible to pass any keyword arguments to astropy.visualization.wcsaxes.WCSAxes.draw(). Previously passing any keyword arguments would have errored anyway, as matplotlib.axes.Axes.draw() does not accept keyword arguments. [#14772]

Bug Fixes

astropy.cosmology

• The exponent in w0wzCDM.de_density_scale has been corrected to 3, from -3. This correction has also been made to the scalar inv_efunc cpython functions. [#14991]

astropy.io.fits

• Fix crash when a PrimaryHDU has a GROUPS keyword with a non-boolean value (i.e. not a random-groups HDU). [#14998]

• Fixed a bug that caused Cutout2D to not work correctly with CompImageHDU.section [#14999]

• Fixed a bug that caused compressed images with TFORM missing the optional ‘1’ prefix to not be readable. [#15001]

astropy.io.misc

• Updated astropy.io.misc.yaml so dump()` with a numpy object array or ``load() with YAML representing a numpy object array both raise TypeError. This prevents problems like a segmentation fault. [#15373]

astropy.io.votable

• Output of repr for VOTable instance now clearly shows it is a VOTable and not generic astropy Table. [#14702]

• Fixed a bug in convert_to_writable_filelike where GzipFile was not closed properly. [#15359]

astropy.modeling

• All models can be pickled now. [#14902]

astropy.nddata

• Restore bitmask propagation behavior in NDData.mask, plus a fix for arithmetic between masked and unmasked NDData objects. [#14995]

astropy.table

• Fix a bug where table indexes were not using a stable sort order. This was causing the order of rows within groups to not match the original table order when an indexed table was grouped. [#14907]

• Fixed issue #14964 that when grouping a Table on a mixin column such as Quantity or Time, the grouped table keys did not reflect the original column values. For Quantity this meant that the key values were pure float values without the unit, while for Time the key values were the pair of jd1 and jd2 float values. [#14966]

astropy.units

• In VOunits, “pix”, “au”, “a”, and “ct” are removed from the list of deprecated units. [#14885]

• In VOUnit, the spaces around the slash were removed in the formatting of fractions, and fractional powers now also use the “**” operator. [#15282]

astropy.utils

• For Masked, np.ptp and the .ptp() method now properly account for the mask, ensuring the result is identical to subtracting the maximum and minimum (with the same arguments). [#15380]

astropy.wcs

• wcs.validate(filename) now properly closes the file handler. [#15054]

Other Changes and Additions

• Compatibility with Python 3.12. [#14784]

• Moved International Earth Rotation and Reference Systems (IERS) and Leap Second files out into standalone astropy-iers-data package, maintaining full backward-compatibility in the astropy.utils.iers API, but deprecation warnings may be issued when certain files are accessed directly. [#14819]

• The minimum supported version of NumPy is now 1.22. [#15006]

• Switch from using setup.cfg for project configuration to using pyproject.toml. [#15247]

Version v5.3.3 (2023-09-07)

Bug Fixes

astropy.coordinates

• TransformGraph.to_dot_graph() now throws an exception for invalid savelayout.

astropy.cosmology

• The exponent of w0wzCDM functions in inv_efunc has been corrected to 3, from -3. [#15224]

astropy.modeling

• Astropy modeling can filter non-finite data values using the filter_non_finite keyword argument in a fitter call. Now when filter_non_finite is True, non-finite weights will also be filtered to prevent crashes in LevMarLSQFitter. [#15215]

astropy.units

• Fixed astropy.units.Quantity’s implementation of numpy.nanmedian(), where for Numpy >= 1.25 an exception was raised for some array shapes and axis combinations. [#15228]

Other Changes and Additions

• v5.3.x will not support NumPy 2.0 or later. [#15234]

Version 5.3.2 (2023-08-11)

Bug Fixes

astropy.coordinates

• Fixed import when called with Python -OO flag. [#15037]

astropy.nddata

• Fix for collapse operations on NDData without masks or units. [#15082]

astropy.units

• Modified the implementation of np.power() for instances of Quantity to allow any array as the second operand if all its elements have the same value. [#15101]

Version 5.3.1 (2023-07-06)

Bug Fixes

astropy.cosmology

• The exponent in wowzCDM.de_density_scale has been corrected to 3, from -3. [#14991]

astropy.io.fits

• Fix crash when a PrimaryHDU has a GROUPS keyword with a non-boolean value (i.e. not a random-groups HDU). [#14998]

• Fixed a bug that caused Cutout2D to not work correctly with CompImageHDU.section [#14999]

• Fixed a bug that caused compressed images with TFORM missing the optional ‘1’ prefix to not be readable. [#15001]

astropy.modeling

• All models can be pickled now. [#14902]

astropy.nddata

• Restore bitmask propagation behavior in NDData.mask, plus a fix for arithmetic between masked and unmasked NDData objects. [#14995]

astropy.table

• Fix a bug where table indexes were not using a stable sort order. This was causing the order of rows within groups to not match the original table order when an indexed table was grouped. [#14907]

astropy.units

• In VOunits, “pix”, “au”, “a”, and “ct” are removed from the list of deprecated units. [#14885]

Version 5.3 (2023-05-22)

New Features

astropy.coordinates

• Add optional parameter refresh_cache to EarthLocation.of_site() and EarthLocation.get_site_names() to force the download of the latest site registry. [#13993]

• Added atol argument to function is_O3 and is_rotation in matrix utilities. [#14371]

• A new class astropy.coordinates.StokesCoord has been added to represent world coordinates describing polarization state. This change introduces a breaking change to the return value of astropy.wcs.WCS.pixel_to_world where before a u.Quantity object would be returned containing numerical values representing a Stokes profile now a StokesCoord object is returned. The previous numerical values can be accessed with StokesCoord.value. [#14482]

• Add an optional parameter location to EarthLocation.get_itrs() to allow the generation of topocentric ITRS coordinates with respect to a specific location. [#14628]

astropy.cosmology

• Two new cosmologies have been added, FlatwpwaCDM and Flatw0wzCDM, which are the flat variants of wpwaCDM and w0wzCDM, respectively. [#12353]

astropy.io.ascii

• Add ability to read and write an RST (reStructuredText) ASCII table that includes additional header rows specifying any or all of the column dtype, unit, format, and description. This is available via the new header_rows keyword argument. [#14182]

astropy.io.fits

• Added support for >3D data in CompImageHDU [#14252]

• Added a CompImageHDU.section property which can be used to efficiently access subsets of the data, similarly to ImageHDU.section. When using this, only the tiles required to cover the section are read from disk and decompressed. [#14353]

• Added support for 'NOCOMPRESS' for the compression_type option in CompImageHDU. [#14408]

• Added new properties compression_type and tile_shape on CompImageHDU, giving the name of the compression algorithm and the shape of the tiles in the tiled compression respectively. [#14428]

• Do not call gc.collect() when closing a CompImageHDU object as it has a large performance penalty. [#14576]

• VLA tables can now be written with the unified I/O interface. When object types are present or the VLA contains different types a TypeError is thrown. [#14578]

astropy.io.misc

• Add support for writing/reading fixed-size and variable-length array columns to the parquet formatter. [#14237]

astropy.io.votable

• Added a method get_infos_by_name to make it easier to implement DALI-compliant protocols [#14212]

• Updating the built-in UCD list to upstream 1.5 (which requires a minor update to the parser) [#14554]

astropy.modeling

• Enable check for poorly conditioned fits in LinearLSQFitter for polynomial models with fixed inputs. [#14037]

astropy.nddata

• astropy.nddata.NDDataArray now has collapsing methods like sum, mean, min, and max which operate along any axes, and better support for astropy.utils.Masked objects. [#14175]

astropy.stats

• vonmisesmle has now functioning “weights” and “axis” parameters that work equivalently to the rest of the functions in the circstats module (circmean, rayleightest, etc.) [#14533]

astropy.table

• Table and QTable can now use the | and |= operators for dictionary-style merge and update. [#14187]

astropy.time

• Add a leap_second_strict argument to the Time.to_datetime() method. This controls the behavior when converting a time within a leap second to the datetime format and can take the values raise (the default), warn, or silent. [#14606]

astropy.timeseries

• Adds the astropy.timeseries.LombScargleMultiband class, which is an extension of the astropy.timeseries.LombScargle class. It enables the generation of periodograms for datasets with measurements taken in more than one photometric band. [#14016]

• Add unit_parse_strict parameter to the Kepler reader to control the warnings emitted when reading files. [#14294]

astropy.units

• Add support for degrees Celsius for FITS. Parsing “Celsius” and “deg C” is now supported and astropy will output “Celsius” into FITS.

  Note that “deg C” is only provided for compatibility with existing FITS files, as it does not conform to the normal unit standard, where this should be read as “degree * Coulomb”. Indeed, compound units like “deg C kg-1” will still be parsed as “Coulomb degree per kilogram”. [#14042]

• Enabled the equal_nan keyword argument for np.array_equal() when the arguments are astropy.units.Quantity instances. [#14135]

• Allow “console” and “unicode” formats for conversion to string of function units. [#14407]

• Add a “fraction” options to all the unit format classes, which determine whether, if a unit has bases raised to a negative power, a string representation should just show the negative powers (fraction=False) or use a fraction, and, in the latter case, whether to use a single-line representation using a solidus (fraction='inline' or fraction=True) or, if the format supports it, a multi-line presentation with the numerator and denominator separated by a horizontal line (fraction='multiline'). [#14449]

astropy.utils

• The mean method on NDDataArray now avoids a division by zero warning when taking the mean of a fully-masked slice (and still returns np.nan). [#14341]

• Ensure we can read the newer IERS_B files produced by the International Earth Rotation and Reference Systems Service, and point astropy.utils.iers.IERS_B_URL to the new location. [#14382]

API Changes

astropy.coordinates

• get_moon() is deprecated and may be removed in a future version of astropy. Calling get_moon(...) should be replaced with get_body("moon", ...). [#14354]

astropy.io.fits

• Deprecate the auto-fixing of tile sizes for HCOMPRESS_1 tiled image compression when the tile size could be changed by +1 to make it acceptable. [#14410]

• The tile_size= argument to CompImageHDU has been deprecated as it was confusing that it was required to be in the opposite order to the data shape (it was in header rather than Numpy order). Instead, users should make use of the tile_shape= argument which is in Numpy shape order. [#14428]

astropy.modeling

• Deprecate the humlicek2 method for Voigt1D in favor of using the wofz method using the scipy.special.wofz implementation of the Fadeeva function whenever scipy is installed. [#14013]

• Deprecated astropy.modeling.utils.comb() function in favor of comb() from math standard library. [#14038]

• Propagate measurement uncertainties via the weights keyword argument into the parameter covariances. [#14519]

astropy.units

• The conversion of astropy.units.Quantity to bool that was deprecated since astropy 3.0 now raises a ValueError. This affects statements like if quantity. Use explicit comparisons like if quantity.value != 0 or if quantity is not None instead. [#14124]

• Operations on Quantity in tables are sped up by only copying info when it makes sense (i.e., when the object can still logically be thought of as the same, such as in unit changes or slicing). info is no longer copied if a Quantity is part of an operation. [#14253]

• The Quantity.nansum method has been deprecated. It was always weird that it was present, since ndarray does not have a similar method, and the other nan* functions such as nanmean did not have a corresponding method. Use np.nansum(quantity) instead. [#14267]

• The unused units.format.Unscaled format class has been deprecated. [#14417]

• The order in which unit bases are displayed has been changed to match the order bases are stored in internally, which is by descending power to which the base is raised, and alphabetical after. This helps avoid monstrosities like beam^-1 Jy for format='fits'.

  Note that this may affect doctests that use quantities with complicated units. [#14439]

astropy.utils

• For Masked instances, the where argument for any ufunc can now also be masked (with any masked elements masked in the output as well). This is not very useful in itself, but avoids problems in conditional functions (like np.add(ma, 1, where=ma>10)). [#14590]

astropy.visualization

• The pixel attribute of astropy.visualization.wcsaxes.frame.Spine is deprecated and will be removed in a future astropy version. Because it is (in general) not possible to correctly calculate pixel coordinates before Matplotlib is drawing a figure, instead set the world or data coordinates of the Spine using the appropriate setters. [#13989]

• Passing a bare number as the coord_wrap argument to CoordinateHelper.set_coord_type is deprecated. Pass a Quantity with units equivalent to angular degrees instead.

  The .coord_wrap attribute of CoordinateHelper is now a Quantity instead of a bare number. [#14050]

Bug Fixes

astropy.coordinates

• Angle.to_string() was changed to ensure it matches the behaviour of Quantity.to_string() in having a space between the value and the unit for display with non-degree and hourangle units (i.e., the case in which units are displayed by their name; the sexagesimal case for degrees or hourangle that uses symbols is not changed). [#14379]

astropy.io.ascii

• Fix an issue in the io.ascii QDP format reader to allow lower-case commands in the table data file. Previously it required all upper case in order to parse QDP files. [#14365]

astropy.io.fits

• Compressing/decompressing a floating point dataset containing NaN values will no longer read in the whole tile as NaNs.

  Fixed segmentation faults that occurred when compressing/decompressing data with the PLIO_1 algorithm. [#14252]

• Card now uses the default Python representation for floating point values. [#14508]

• ImageHDU now properly rejects Numpy scalars, avoiding data corruption. [#14528]

• Fix issues with double quotes in CONTINUE cards. [#14598]

• Fixes an issue where FITS_rec was incorrectly raising a ValueError exception when the heapsize was greater than 2**31 when the Column type was ‘Q’ instead of ‘P’. [#14810]

astropy.io.misc

• Columns with big-endian byte ordering (such as those read in from a FITS table) can now be serialized with Parquet. [#14373]

astropy.modeling

• Bugfix for using getter/setter in properties to adjust the internal (computational) value of a property vs its external proxy value when the values involve units. [#14512]

• Fix issue with filter_non_finite option when fitting with weights via passing the weights through the non-finite-filter alongside the input data. [#14695]

• Fixed an issue with Parameter where a getter could be input without a setter (or vice versa). [#14708]

astropy.time

• Using quantities with units of time for Time format ‘decimalyear’ will now raise an error instead of converting the quantity to days and then interpreting the value as years. An error is raised instead of attempting to interpret the unit as years, since the interpretation is ambiguous: in ‘decimaltime’ years are equal to 365 or 366 days, while for regular time units the year is defined as 365.25 days. [#14566]

astropy.uncertainty

• Ensure that Distribution can be compared with == and != with regular arrays or scalars, and that inplace operations like dist[dist<0] *= -1 work. [#14421]

astropy.units

• Modified astropy.units.Quantity.__array_ufunc__() to return NotImplemented instead of raising a ValueError if the inputs are incompatible. [#13977]

• Modified the behavior of numpy.array_equal() and numpy.array_equiv() to return False instead of raising an error if their arguments are astropy.units.Quantity instances with incompatible units. [#14163]

• Spaces have been regularized for the unicode and console output formats: no extraneous spaces in front of the unit, and always a space between a possible scale factor and the unit. [#14413]

• Prefixed degrees and arcmin are now typeset without using the symbol in latex and unicode formats (i.e., mdeg instead of m°), as was already the case for arcsec. [#14419]

• Ensure the unit is kept in np.median even if the result is a scalar nan (the unit was lost for numpy < 1.22). [#14635]

• Ensure that Quantity with structured dtype can be set using non-structured Quantity (if units match), and that structured dtype names are inferred correctly in the creation of StructuredUnit, thus avoiding mismatches when setting units. [#14680]

astropy.utils

• When using astropy in environments with sparse file systems (e.g., where the temporary directory and astropy data directory resides in different volumes), os.rename may fail with OSError: [Errno 18] Invalid cross-device link. This may affect some clean-up operations executed by the data module, causing them to fail. This patch is to catch OSError with errno == EXDEV (i.e., Errno 18) when performing these operations and try to use shutil.move instead to relocate the data. [#13730]

• Ensure masks are propagated correctly for outer methods of ufuncs also if one of the inputs is not actually masked. [#14624]

astropy.visualization

• The location of a astropy.visualization.wcsaxes.frame.Spine in a plot is now correctly calculated when the DPI of a figure changes between a WCSAxes being created and the figure being drawn. [#13989]

• CoordinateHelper.set_ticks() now accepts number=0. Previously it errored. [#14160]

• WCSAxes.plot_coord and plot_scatter now work correctly for APE 14 compliant WCSes where the units are not always converted to degrees. [#14251]

• Fixed a bug where coordinate overlays did not automatically determine the longitude wrap angle or the appropriate units. [#14326]

astropy.wcs

• Fix bugs with high-level WCS API on wcs.WCS object when using -TAB coordinates. [#13571]

• Fixed a bug in how WCS handles PVi_ja header coefficients when CTYPE has -SIP suffix and in how code detects TPV distortions. [#14295]

Other Changes and Additions

• The minimum supported version of Python is now 3.9, changing from 3.8. [#14286]

• The minimum supported version of Numpy is now 1.21. [#14349]

• The minimum supported version of matplotlib is now 3.3. [#14286, #14321]

• astropy no longer publishes wheels for i686 architecture. [#14517]

• Added a pre-commit configuration for codespell. [#13985]

• Removed a large fraction of the bundled CFITSIO code and internally refactored FITS compression-related code, which has resulted in a speedup when compiling astropy from source (40% faster in some cases). [#14252]

• The CFITSIO library is no longer bundled in full with astropy and the option to build against an external installation of CFITSIO has now been removed, so the ASTROPY_USE_SYSTEM_CFITSIO environment variable will be ignored during building. [#14311]

• Updated CDS URL for Sesame look-up as the old URL is deprecated. [#14681]

Version 5.2.2 (2023-03-28)

Bug Fixes

astropy.io.ascii

• CDS and MRT tables with units that contain with multiple divisions, such as km/s/Mpc now parse correctly as being equal to km/(s.Mpc). [#14369]

astropy.io.fits

• Fix FITSDiff when table contains a VLA column with the Q type. [#14539]

astropy.table

• Fix a bug when creating a QTable when a Quantity input column is present and the units argument modifies the unit of that column. This now works as expected where previously this caused an exception. [#14357]

astropy.units

• CDS units with multiple divisions, such as km/s/Mpc now parse correctly as being equal to km/(s.Mpc). [#14369]

astropy.wcs

• Fixed a bug that caused subclasses of BaseHighLevelWCS and HighLevelWCSMixin to not work correctly under certain conditions if they did not have world_n_dim and pixel_n_dim defined on them. [#14495]

Version 5.2.1 (2023-01-06)

Bug Fixes

astropy.coordinates

• Fix to ITRS frame earth_location attribute to give the correct result for a topocentric frame. [#14180]

astropy.cosmology

• Bounds are no longer passed to the scipy minimizer for methods Brent and Golden. The scipy minimizer never used the bounds but silently accepted them. In scipy v1.11.0.dev0+ an error is raised, so we now pass None as the bounds to the minimizer. Users should not be affected by this change. [#14232]

astropy.io.fits

• Tables with multidimensional variable length array can now be properly read and written. [#13417]

astropy.units

• Modified the behavior of numpy.histogram(), numpy.histogram_bin_edges(), numpy.histogram2d(), and numpy.histogramdd() so that the range argument must a compatible instance of astropy.units.Quantity if the other arguments are instances of astropy.units.Quantity. [#14213]

astropy.visualization

• Improved the performance of drawing WCSAxes grids by skipping some unnecessary computations. [#14164]

• Fixed WCSAxes sometimes triggering a NumPy RuntimeWarning when determining the coordinate range of the axes. [#14211]

Other Changes and Additions

• Fix compatibility with Numpy 1.24. [#14193]

Version 5.2 (2022-12-12)

New Features

astropy.coordinates

• Adds new topocentric ITRS frame and direct transforms to and from the observed frames AltAz and HADec with the ability to add or remove refraction corrections as required. Since these frames are all within the ITRS, there are no corrections applied other than refraction in the transforms. This makes the topocentric ITRS frame and these transforms convenient for observers of near Earth objects where stellar aberration should be omitted. [#13398]

• Allow comparing SkyCoord to frames with data. [#13477]

astropy.cosmology

• Cosmology instance can be parsed from or converted to a HTML table using the new HTML methods in Cosmology’s to/from_format I/O. [#13075]

• A new comparison function has been added – cosmology_equal() – that mirrors its numpy counterpart but allows for the arguments to be converted to a Cosmology and to compare flat cosmologies with their non-flat equivalents. [#13104]

• Cosmology equivalence for flat FLRW cosmologies has been generalized to apply to all cosmologies using the FlatCosmology mixin. [#13261]

• The cosmological redshift unit now has a physical type of "redshift". [#13561]

astropy.io.ascii

• Add ability to read and write a fixed width ASCII table that includes additional header rows specifying any or all of the column dtype, unit, format, and description. This is available in the fixed_width and fixed_width_two_line formats via the new header_rows keyword argument. [#13734]

astropy.io.fits

• Added support to the io.fits API for reading and writing file paths of the form ~/file.fits or ~<username>/file.fits, referring to the home directory of the current user or the specified user, respectively. [#13131]

• Added support for opening remote and cloud-hosted FITS files using the fsspec package, which has been added as an optional dependency. [#13238]

astropy.io.votable

• Added support in io.votable for reading and writing file paths of the form ~/file.xml or ~<username>/file.xml, referring to the home directory of the current user or the specified user, respectively. [#13149]

astropy.modeling

• Add option to non-linear fitters which enables automatic exclusion of non-finite values from the fit data. [#13259]

astropy.nddata

• Modified Cutout2D to allow objects of type astropy.io.fits.Section to be passed to the data parameter. [#13238]

• Add a PSF image representation to astropy.nddata.NDData and astropy.nddata.CCDData. [#13743]

astropy.table

• An Astropy table can now be converted to a scalar NumPy object array. For NumPy >= 1.20, a list of Astropy tables can be converted to an NumPy object array of tables. [#13469]

astropy.time

• Added the astropy.time.Time.mean() method which also enables the numpy.mean() function to be used on instances of astropy.time.Time. [#13508]

• Improve the performance of getting the string representation of a large Time or TimeDelta object. This is done via a new to_string() method that does the time string format conversion only for the outputted values. Previously the entire array was formatted in advance. [#13555]

astropy.units

• It is now possible to use unit format names as string format specifiers for a Quantity, e.g. f'{1e12*u.m/u.s:latex_inline}' now produces the string '$1 \\times 10^{12} \\; \\mathrm{m\\,s^{-1}}$'. [#13050]

• Ensure that the argmin and argmax methods of Quantity support the keepdims argument when numpy does (numpy version 1.22 and later). [#13329]

• numpy.lib.recfunctions.merge_arrays() is registered with numpy overload for Quantity. [#13669]

• Added SI prefixes for quecto (“q”, \(10^{-30}\)), ronto (“r”, \(10^{-27}\)), ronna (“R”, \(10^{27}\)), and quetta (“Q”, \(10^{30}\)). [#14046]

astropy.utils

• Added the use_fsspec, fsspec_kwargs, and close_files arguments to utils.data.get_readable_fileobj. [#13238]

• Ensure that the argmin and argmax methods of Masked instances support the keepdims argument when numpy does (numpy version 1.22 and later). [#13329]

astropy.visualization

• Add helper functions for WCSAxes instances to draw the instrument beam and a physical scale. [#12102]

• Add a scatter_coord method to the wcsaxes functionality based on the existing plot_coord method but that calls matplotlib.pyplot.scatter. [#13562]

• Added a sinh stretch option to simple_norm. [#13746]

• It is now possible to define “tickable” gridlines for the purpose of placing ticks or tick labels in the interior of WCSAxes plots. [#13829]

API Changes

astropy.convolution

• Removed deprecated MexicanHat1DKernel and MexicanHat2DKernel classes. Please use RickerWavelet1DKernel and RickerWavelet2DKernel instead. [#13300]

astropy.units

• Multiplying a LogQuantity like Magnitude with dimensionless physical units by an array will no longer downcast to Quantity. [#12579]

• Quantity normally upcasts integer dtypes to floats, unless the dtype is specifically provided. Before this happened when dtype=None; now the default has been changed to dtype=numpy.inexact and dtype=None has the same meaning as in numpy. [#12941]

• In “in-place unit changes” of the form quantity <<= new_unit, the result will now share memory with the original only if the conversion could be done through a simple multiplication with a scale factor. Hence, memory will not be shared if the quantity has integer `dtype` or is structured, or when the conversion is through an equivalency. [#13638]

• When Quantity is constructed from a structured array and unit is None, the default unit is now structured like the input data. [#13676]

astropy.utils

• astropy.utils.misc.suppress has been removed, use contextlib.suppress instead. astropy.utils.namedtuple_asdict has been removed, instead use method ._asdict on a namedtuple. override__dir__ has been deprecated and will be removed in a future version, see the docstring for the better alternative. [#13636]

• astropy.utils.misc.possible_filename has been removed. [#13661]

astropy.visualization

• Rename number-of-samples keyword nsamples in ZScaleInterval to align with the n_samples keyword used in all other Interval classes in this module. [#13810]

Bug Fixes

astropy.convolution

• Fixed convolution Kernels to ensure the that returned kernels are normalized to sum to one (e.g., Gaussian1DKernel, Gaussian2DKernel). Also fixed the Kernel truncation calculation. [#13299]

• Fix import error with setuptools v65.6.0 by replacing numpy.ctypeslib.load_library with Cython to load the C convolution extension. [#14035]

astropy.coordinates

• BaseCoordinateFrame.get_frame_attr_names() had a misleading name, because it actually provided a dict of attribute names and their default values. It is now deprecated and replaced by BaseCoordinateFrame.get_frame_attr_defaults(). The fastest way to obtain the attribute names is BaseFrame.frame_attributes.keys(). [#13484]

• Fixed bug that caused earth_orientation.nutation_matrix() to error instead of returning output. [#13572]

• Ensure that angle.to_string() continues to work after pickling, and that units passed on to to_string() or the Angle initializer can be composite units (like u.hour**1), which might result from preceding calculations. [#13933]

astropy.io.fits

• report_diff_values() have now two new parameters rtol and atol to make the report consistent with numpy.allclose results. This fixes FITSDiff with multi-dimensional columns. [#13465]

astropy.io.votable

• Fixed two bugs in validator.validator.make_validation_report: - ProgressBar iterator was not called correctly. - make_validation_report now handles input string urls correctly. [#14102]

astropy.timeseries

• Fixed a performance regression in timeseries.aggregate_downsample introduced in Astropy 5.0 / #11266. [#13069]

astropy.units

• Unit changes of the form quantity <<= new_unit will now work also if the quantity is integer. The result will always be float. This means that the result will not share memory with the original. [#13638]

• Ensure dimensionless quantities can be added inplace to regular ndarray. [#13913]

astropy.utils

• Fixed an incompatibility with latest Python 3.1x versions that kept astropy.utils.data.download_file from switching to TLS+FTP mode. [#14092]

• np.quantile and np.percentile can now be used on Masked

  arrays and quantities also with keepdims=True. [#14113]

astropy.visualization

• Significantly improve performance of ManualInterval when both limits are specified manually. [#13898]

Other Changes and Additions

• The deprecated private astropy._erfa module has been removed. Use pyerfa, which is a dependency of astropy and can be imported directly using import erfa. [#13317]

• The minimum version required for numpy is now 1.20 and that for scipy 1.5. [#13885]

• Updated the bundled CFITSIO library to 4.2.0. [#14020]

Version 5.1.1 (2022-10-23)

API Changes

astropy.wcs

• The pixel argument to astropy.visualization.wcsaxes.ticklabels.TickLabels.add no longer does anything, is deprecated, and will be removed in a future astropy version. It has been replaced by a new required data argument, which should be used to specify the data coordinates of the tick label being added.

  This changes has been made because it is (in general) not possible to correctly calculate pixel coordinates before Matplotlib is drawing a figure. [#12630]

Bug Fixes

astropy.coordinates

• Fixed a bug that prevented SkyOffsetFrame instances to be pickled by adding a custom __reduce__ method to the class (see issue #9249). [#13305]

• Fixed the check for invalid Latitude values for float32 values. Latitude now accepts the float32 value of pi/2, which was rejected before because a comparison was made using the slightly smaller float64 representation. See issue #13708. [#13745]

astropy.io.ascii

• Fixed confusing chained exception messages of read() function when it fails. [#13170]

• When writing out a Table to HTML format, the formats keyword argument to the write() method will now be applied. [#13453]

astropy.io.fits

• heapsize is now checked for VLA tables. An error is thrown whether P format is used but the heap size is bigger than what can be indexed with a 32 bit signed int. [#13429]

• Fix parsing of ascii TFORM when precision is missing. [#13520]

• A compressed image HDU created from the header of a PRIMARY HDU, now correctly updates ‘XTENSION’ and ‘SIMPLE’ keywords. [#13557]

• Empty variable-length arrays are now properly handled when pathological combinations of heapoffset and heapsize are encountered. [#13621]

• PCOUNT and GCOUNT keywords are now removed from an uncompressed Primary header, for compliance with fitsverify behavior. [#13753]

astropy.modeling

• Bugfix for using MagUnit units on model parameters. [#13158]

• Fix bug in using non-linear fitters to fit 0-degree polynomials using weights. [#13628]

astropy.table

• Fix a problem where accessing one field of a structured column returned a Column with the same info as the original column. This resulted in unintuitive behavior in general and an exception if the format for the column was set. [#13269]

• Tables with columns with structured data can now be properly stacked and joined. [#13306]

• Update jQuery to 3.6.0, to pick up security fixes. [#13438]

• Fix a Python 3.11 compatibility issue. Ensure that when removing a table column that the pprint_include_names or pprint_exclude_names attributes get updated correctly. [#13639]

• When using add_columns with same indexes in indexes option or without specifying the option, the order of the new columns will now be kept. [#13783]

• Fix a bug when printing or getting the representation of a multidimensional table column that has a zero dimension. [#13838]

• Ensure that mixin columns and their info are not shared between tables even when their underlying data is shared with copy=False. [#13842]

astropy.time

• Fix Time.insert() on times which have their out_subfmt set. [#12732]

• Prevent Time() from being initialized with an invalid precision leading to incorrect results when representing the time as a string. [#13068]

• Fix a bug in Time where a date string like “2022-08-01.123” was being parsed as an ISO-format time “2022-08-01 00:00:00.123”. The fractional part at the end of the string was being taken as seconds. Now this raises an exception because the string is not in ISO format. [#13731]

astropy.units

• Significantly improved the performance of parsing composite units with the FITS format, by ensuring the detailed_exception argument is properly passed on and thus used. [#12699]

• Ensure that np.concatenate on quantities can take a dtype argument (added in numpy 1.20). [#13323]

• Ensure that the units of any initial argument to reductions such as np.add.reduce (which underlies np.sum) are properly taken into account. [#13340]

astropy.utils

• Ensure that np.concatenate on masked data can take a dtype argument (added in numpy 1.20). [#13323]

• Fix error when suppressing download progress bar while using non-default sys.stdout stream. [#13352]

• Ensure str and repr work properly for Masked versions of structured subarrays. [#13404]

• If an attribute is created using deprecated_attribute() with the alternative argument then getting or setting the value of the deprecated attribute now accesses its replacement. [#13824]

astropy.visualization

• Fixed calling .tight_layout() on a WCSAxes. [#12418]

astropy.wcs

• WCS.pixel_to_world now creates an EarthLocation object using MJD-AVG if present before falling back to the old behaviour of using MJD-OBS. [#12598]

• The locations of WCSAxes ticks and tick-labels are now correctly calculated when the DPI of a figure changes between a WCSAxes being created and the figure being drawn, or when a rasterized artist is added to the WCSAxes. [#12630]

• Fix a bug where SlicedLowLevelWCS.world_to_pixel_values would break when the result of the transform is dependent on the coordinate of a sliced out pixel. [#13579]

• Updated bundled WCSLIB version to 7.12. This update includes bug fixes to wcssub() in how it handles temporal axes with -TAB and fixes handling of status returns from linp2x() and linx2p() relating to distortion functions, in particular affecting TPV distortions - see #13509. For a full list of changes - see http://www.atnf.csiro.au/people/mcalabre/WCS/CHANGES or astropy/cextern/wcslib/CHANGES. [#13635]

• Fixed WCS validation not working properly if HDUList is needed for multi-extension FITS file. [#13668]

Other Changes and Additions

• Development wheels of astropy should now be installed from https://pypi.anaconda.org/astropy/simple instead of from https://pkgs.dev.azure.com/astropy-project/astropy/_packaging/nightly/pypi/simple. [#13431]

• Compatibility with Python 3.11, 3.10.7, 3.9.14, 3.8.14 [#13614]

Version 5.1 (2022-05-24)

New Features

astropy.coordinates

• The ephemeris used in astropy.coordinates can now be set to any version of the JPL ephemeris available from https://naif.jpl.nasa.gov/pub/naif/generic_kernels/spk/planets/. [#12541]

• Angle.to_string() now accepts the 'latex_inline' unit format. [#13056]

astropy.cosmology

• Cosmology instance can be parsed from or converted to a YAML string using the new “yaml” format in Cosmology’s to/from_format I/O. [#12279]

• Register “astropy.row” into Cosmology’s to/from format I/O, allowing a Cosmology instance to be parse from or converted to an Astropy Table Row. [#12313]

• A method clone has been added to Parameter to quickly deep copy the object and change any constructor argument. A supporting equality method is added, and repr is enhanced to be able to roundtrip – eval(repr(Parameter())) – if the Parameter’s arguments can similarly roundtrip. Parameter’s arguments are made keyword-only. [#12479]

• Add methods Otot and Otot0 to FLRW cosmologies to calculate the total energy density of the Universe. [#12590]

• Add property is_flat to cosmologies to calculate the curvature of the Universe. Cosmology is now an abstract class and subclasses must override the abstract property is_flat. [#12606]

• For converting a cosmology to a mapping, two new boolean keyword arguments are added: cosmology_as_str for turning the class reference to a string, instead of the class object itself, and move_from_meta to merge the metadata with the rest of the returned mapping instead of adding it as a nested dictionary. [#12710]

• Register format “astropy.cosmology” with Cosmology I/O. [#12736]

• Cosmological equivalency (Cosmology.is_equivalent) can now be extended to any Python object that can be converted to a Cosmology, using the new keyword argument format. This allows e.g. a properly formatted Table to be equivalent to a Cosmology. [#12740]

• The new module cosmology/tests/helper.py has been added to provide tools for testing the cosmology module and related extensions. [#12966]

• A new property nonflat has been added to flat cosmologies (FlatCosmologyMixin subclasses) to get an equivalent cosmology, but of the corresponding non-flat class. [#13076]

• clone has been enhanced to allow for flat cosmologies to clone on the equivalent non-flat cosmology. [#13099]

• cosmology file I/O uses the Unified Table I/O interface, which has added support for reading and writing file paths of the form ~/file.ecsv or ~<username>/file.ecsv, referring to the home directory of the current user or the specified user, respectively. [#13129]

astropy.io.ascii

• Simplify the way that the converters argument of io.ascii.read is provided. Previously this required wrapping each data type as the tuple returned by the io.ascii.convert_numpy() function and ensuring that the value is a list. With this update you can write converters={'col1': bool} to force conversion as a bool instead of the previous syntax converters={'col1': [io.ascii.convert_numpy(bool)]}. Note that this update is back-compatible with the old behavior. [#13073]

• Added support in io.ascii for reading and writing file paths of the form ~/file.csv or ~<username>/file.csv, referring to the home directory of the current user or the specified user, respectively. [#13130]

astropy.io.fits

• Add option unit_parse_strict to astropy.io.fits.connect.read_table_fits to enable warnings or errors about invalid FITS units when using astropy.table.Table.read. The default for this new option is "warn", which means warnings are now raised for columns with invalid units. [#11843]

• Changes default FITS behavior to use buffered I/O rather than unbuffered I/O for performance reasons. [#12081]

• astropy.io.fits.Header now has a method to calculate the size (in bytes) of the data portion (with or without padding) following that header. [#12110]

astropy.io.misc

• Allow serialization of model unit equivalencies. [#10198]

• Built-in Cosmology subclasses can now be converted to/from YAML with the functions dump and load in astropy.io.misc.yaml. [#12279]

• Add asdf support for Cosine1D, Tangent1D, ArcSine1D, ArcCosine1D, and ArcTangent1D models. [#12895]

• Add asdf support for Spline1D models. [#12897]

astropy.io.registry

• Added support to the Unified Table I/O interface for reading and writing file paths of the form ~/file.csv or ~<username>/file.csv, referring to the home directory of the current user or the specified user, respectively. [#13129]

astropy.modeling

• Add new fitters based on scipy.optimize.least_squares method of non-linear least-squares optimization: [#12051]

  • TRFLSQFitter using the Trust Region Reflective algorithm.

  • LMLSQFitter using the Levenberg-Marquardt algorithm (implemented by scipy.optimize.least_squares).

  • DogBoxLSQFitter using the dogleg algorithm.

• Enable direct use of the ignored feature of ModelBoundingBox by users in addition to its use as part of enabling CompoundBoundingBox. [#12384]

• Switch modeling.projections to use astropy.wcs.Prjprm wrapper internally and provide access to the astropy.wcs.Prjprm structure. [#12558]

• Add error to non-finite inputs to the LevMarLSQFitter, to protect against soft scipy failure. [#12811]

• Allow the Ellipse2D and Sersic2D theta parameter to be input as an angular quantity. [#13030]

• Added Schechter1D model. [#13116]

astropy.nddata

• Add support for converting between uncertainty types. This uncertainty conversion system uses a similar flow to the coordinate subsystem, where Cartesian is used as the common system. In this case, variance is used as the common system. [#12057]

• The as_image_hdu option is now available for CCDData.to_hdu and CCDData.write. This option allows the user to get an ImageHDU as the first item of the returned HDUList, instead of the default PrimaryHDU. [#12962]

• File I/O through nddata.CCDData uses the Unified I/O interface, which has added support for reading and writing file paths of the form ~/file.csv or ~<username>/file.csv, referring to the home directory of the current user or the specified user, respectively. [#13129]

astropy.table

• A new keyword-only argument kind was added to the Table.sort method to specify the sort algorithm. [#12637]

• Columns which are numpy structured arrays are now fully supported, effectively allowing tables within tables. This applies to Column, MaskedColumn, and Quantity columns. These structured data columns can be stored in ECSV, FITS, and HDF5 formats. [#12644]

• Improve the performance of np.searchsorted by a factor of 1000 for a bytes-type Column when the search value is str or an array of str. This happens commonly for string data stored in FITS or HDF5 format files. [#12680]

• Add support for using mixin columns in group aggregation operations when the mixin supports the specified operation (e.g. np.sum works for Quantity but not Time). In cases where the operation is not supported the code now issues a warning and drops the column instead of raising an exception. [#12825]

• Added support to the Unified Table I/O interface for reading and writing file paths of the form ~/file.csv or ~<username>/file.csv, referring to the home directory of the current user or the specified user, respectively. [#13129]

astropy.time

• Add support for calling numpy.linspace() with two Time instances to generate a or multiple linearly spaced set(s) of times. [#13132]

astropy.units

• structured_to_unstructured and unstructured_to_structured in numpy.lib.recfunctions now work with Quantity. [#12486]

• Implement multiplication and division of LogQuantities and numbers [#12566]

• New doppler_redshift equivalency to convert between Doppler redshift and radial velocity. [#12709]

• Added the where keyword argument to the mean(),``var()``, std() and nansum() methods of astropy.units.Quantity. Also added the intial keyword argument to astropy.units.Quantity.nansum(). [#12891]

• Added “Maxwell” as a unit for magnetic flux to the CGS module. [#12975]

• Quantity.to_string() and FunctionUnitBase.to_string() now accept the 'latex_inline' unit format. The output of StructuredUnit.to_string() when called with format='latex_inline' is now more consistent with the output when called with format='latex'. [#13056]

astropy.utils

• Added the where keyword argument to the mean(), var(), std(), any(), and all() methods of astropy.utils.masked.MaskedNDArray. [#12891]

• Improve handling of unavailable IERS-A (predictive future Earth rotation) data in two ways. First, allow conversions with degraded accuracy if the IERS-A data are missing or do not cover the required time span. This is done with a new config item conf.iers_degraded_accuracy which specifies the behavior when times are outside the range of IERS table. The options are ‘error’ (raise an IERSRangeError, default), ‘warn’ (issue a IERSDegradedAccuracyWarning) or ‘ignore’ (ignore the problem). Second, the logic for auto-downloads was changed to guarantee that no matter what happens with the IERS download operations, only warnings will be issued. [#13052]

astropy.wcs

• astropy.wcs.Celprm and astropy.wcs.Prjprm have been added to allow access to lower level WCSLIB functionality and to allow direct access to the cel and prj members of Wcsprm. [#12514]

• Add temporal properties for convenient access of/selection of/testing for the TIME axis introduced in WCSLIB version 7.8. [#13094]

API Changes

astropy.coordinates

• The dms_to_degrees and hms_to_hours functions (and implicitly tuple-based initialization of Angle) is now deprecated, as it was difficult to be sure about the intent of the user for signed values of the degrees/hours, minutes, and seconds. [#13162]

astropy.cosmology

• The already deprecated Planck18_arXiv_v2 has been removed. Use Planck18 instead [#12354]

• default_cosmology.get_cosmology_from_string is deprecated and will be removed in two minor versions. Use getattr(astropy.cosmology, <str>) instead. [#12375]

• In I/O, conversions of Parameters move more relevant information from the Parameter to the Column. The default Parameter format_spec is changed from ".3g" to "". [#12612]

• Units of redshift are added to z_reion in built-in realizations’ metadata. [#12624]

• Cosmology realizations (e.g. Planck18) and parameter dictionaries are now lazily loaded from source files. [#12746]

• The Cosmology Parameter argument “fmt” for specifying a format spec has been deprecated in favor of using the built-in string representation from the Parameter’s value’s dtype. [#13072]

astropy.io.ascii

• When reading an ECSV file, changed the type checking to issue an InvalidEcsvDatatypeWarning instead of raising a ValueError exception if the datatype of a column is not recognized in the ECSV standard. This also applies to older versions of ECSV files which used to silently proceed but now warn first. [#12841]

astropy.io.fits

• Removed deprecated clobber argument from functions in astropy.io.fits. [#12258]

• Add -s/--sort argument to fitsheader to sort the fitsort-mode output. [#13106]

astropy.io.misc

• Deprecate asdf in astropy core in favor of the asdf-astropy package. [#12903, #12930]

astropy.modeling

• Made astropy.modeling.fitting._fitter_to_model_params and astropy.modeling.fitting._model_to_fit_params public methods. [#12585]

astropy.table

• Change the repr of the Table object to replace embedded newlines and tabs with r'\n' and r'\t' respectively. This improves the display of such tables. [#12631]

• A new keyword-only argument kind was added to the Table.sort method to specify the sort algorithm. The signature of Table.sort was modified so that the reverse argument is now keyword-only. Previously reverse could be specified as the second positional argument. [#12637]

• Changed behavior when a structured numpy.ndarray is added as a column to a Table. Previously this was converted to a NdarrayMixin subclass of ndarray and added as a mixin column. This was because saving as a file (e.g. HDF5, FITS, ECSV) was not supported for structured array columns. Now a structured numpy.ndarray is added to the table as a native Column and saving to file is supported. [#13236]

astropy.tests

• Backward-compatible import of astropy.tests.disable_internet has been removed; use pytest_remotedata.disable_internet from pytest-remotedata instead. [#12633]

• Backward-compatible import of astropy.tests.helper.remote_data has been removed; use pytest.mark.remote_data from pytest-remotedata instead. [#12633]

• The following are deprecated and will be removed in a future release. Use pytest warning and exception handling instead: [#12633]

  • astropy.io.ascii.tests.common.raises

  • astropy.tests.helper.catch_warnings

  • astropy.tests.helper.ignore_warnings

  • astropy.tests.helper.raises

  • astropy.tests.helper.enable_deprecations_as_exceptions

  • astropy.tests.helper.treat_deprecations_as_exceptions

• Backward-compatible plugin astropy.tests.plugins.display has been removed; use pytest-astropy-header instead. [#12633]

astropy.time

• Creating an TimeDelta object with numerical inputs that do not have a unit and without specifying an explicit format, for example TimeDelta(5), now results in a TimeDeltaMissingUnitWarning. This also affects statements like Time("2020-01-01") + 5 or Time("2020-01-05") - Time("2020-01-03") < 5, which implicitly transform the right-hand side into an TimeDelta instance. [#12888]

Bug Fixes

astropy.coordinates

• The machinery that makes observatory locations available as EarthLocation objects is now smarter about processing observatory names from its data files. More names are available for use and the empty string is no longer considered to be a valid name. [#12721]

astropy.io.ascii

• Fixed io.ascii read and write functions for most formats to correctly handle data fields with embedded newlines for both the fast and pure-Python readers and writers. [#12631]

• Fix an issue when writing Time table columns to a file when the time format is one of datetime, datetime64, or ymdhms. Previously, writing a Time column with one of these formats could result in an exception or else an incorrect output file that cannot be read back in. [#12842]

astropy.io.fits

• Add a mask_invalid option to Table.read to allow deactivating the masking of NaNs in float columns and empty strings in string columns. This option is necessary to allow effective use of memory-mapped reading with memmap=True. [#12544]

• Fix CompImageHeader.clear(). [#13102]

astropy.modeling

• Bugfix for ignore functionality failing in ModelBoundingBox when using ignore option alongside passing bounding box data as tuples. [#13032]

astropy.table

• Fixed a bug in Table.show_in_browser using the jsviewer=True option to display the table with sortable columns. Previously the sort direction arrows were not being shown due to missing image files for the arrows. [#12716]

• Fix an issue when writing Time table columns to a file when the time format is one of datetime, datetime64, or ymdhms. Previously, writing a Time column with one of these formats could result in an exception or else an incorrect output file that cannot be read back in. [#12842]

• Fixed a bug where it is not possible to set the .info.format property of a table structured column and get formatted output. [#13233]

• Fixed a bug when adding a masked structured array to a table. Previously this was auto-converted to a NdarrayMixin which loses the mask. With this fix the data are added to the table as a MaskedColumn and the mask is preserved. [#13236]

astropy.time

• Fix an issue when writing Time table columns to a file when the time format is one of datetime, datetime64, or ymdhms. Previously, writing a Time column with one of these formats could result in an exception or else an incorrect output file that cannot be read back in. [#12842]

astropy.utils

• Fixed a bug which caused numpy.interp to produce incorrect results when Masked arrays were passed. [#12978]

• Fixed HAS_YAML not working as intended. [#13066]

astropy.wcs

• Convert NoConvergence errors to warnings in world_to_pixel_values so that callers can work at least with the non converged solution. [#11693]

• Expose the ability to select TIME axis introduced in WCSLIB version 7.8. [#13062]

• Do not call wcstab on wcscopy and copy wtb members from the original WCS. [#13063]

• Updated bundled WCSLIB version to 7.11. This update together with 7.10 includes bug fixes to tabini() and tabcpy() as well as several print formatting enhancements. For a full list of changes - see http://www.atnf.csiro.au/people/mcalabre/WCS/CHANGES [#13171]

• Fixed error that occurred in WCS.world_to_pixel for WCS objects with a spectral axis and observer location information when passing a SpectralCoord that had missing observer or target information. [#13228]

Version 5.0.4 (2022-03-31)

Bug Fixes

astropy.modeling

• Fixed the Gaussian2D bounding_box when theta is an angular Quantity. [#13021]

astropy.utils

• Reverted astropy.utils.iers.iers.IERS_A_URL to maia.usno.navy.mil domain instead of NASA FTP to work around server issues. [#13004]

Other Changes and Additions

• Updated bundled WCSLIB to version 7.9 with several bugfixes and added support for time coordinate axes in wcsset() and wcssub(). The four-digit type code for the time axis will have the first digit set to 4, i.e., four digit code will be 4xxx where x is a digit 0-9. For a full list of bug fixes see https://www.atnf.csiro.au/people/mcalabre/WCS/CHANGES [#12994]

Version 5.0.3 (2022-03-25)

Bug Fixes

astropy.convolution

• Bugfix in astropy.convolution.utils.discretize_model which allows the function to handle a CompoundModel. Before this fix, discretize_model was confusing CompoundModel with a callable function. [#12959]

astropy.io.fits

• Fix write and read FITS tables with multidimensional items, using from_columns without previousely defined ColDefs structure. [#12863]

astropy.io.votable

• Fix VOTable linting to avoid use of shell option. [#12985]

astropy.utils

• Fix XML linting to avoid use of shell option. [#12985]

Other Changes and Additions

• Updated the bundled CFITSIO library to 4.1.0. [#12967]

Version 5.0.2 (2022-03-10)

Bug Fixes

astropy.io.ascii

• Bugfix to add backwards compatibility for reading ECSV version 0.9 files with non-standard column datatypes (such as object, str, datetime64, etc.), which would raise a ValueError in ECSV version 1.0. [#12880]

astropy.io.misc

• Bugfix for units_mapping schema’s property name conflicts. Changes:

  • inputs to unit_inputs

  • outputs to unit_outputs [#12800]

astropy.io.votable

• Fixed a bug where astropy.io.votable.validate was printing output to sys.stdout when the output parameter was set to None. validate now returns a string when output is set to None, as documented. [#12604]

astropy.modeling

• Fix handling of units on scale parameter in BlackBody model. [#12318]

• Indexing on models can now be used with all types of integers (like numpy.int64) instead of just int. [#12561]

• Fix computation of the separability of a CompoundModel where another CompoundModel is on the right hand side of the & operator. [#12907]

• Provide a hook (Model._calculate_separability_matrix) to allow subclasses of Model to define how to compute their separability matrix. [#12900]

astropy.stats

• Fixed a bug in which running kuiper_false_positive_probability(D,N) on distributions with many data points could produce NaN values for the false positive probability of the Kuiper statistic. [#12896]

astropy.wcs

• Fixed a bug due to which naxis, pixel_shape, and pixel_bounds attributes of astropy.wcs.WCS were not restored when an astropy.wcs.WCS object was unpickled. This fix also eliminates FITSFixedWarning warning issued during unpiclikng of the WCS objects related to the number of axes. This fix also eliminates errors when unpickling WCS objects originally created using non-default values for key, colsel, and keysel parameters. [#12844]

Version 5.0.1 (2022-01-26)

Bug Fixes

astropy.coordinates

• Trying to create an instance of astropy.coordinates.Distance by providing both z and parallax now raises the expected ValueError. [#12531]

• Fixed a bug where changing the wrap angle of the longitude component of a representation could raise a warning or error in certain situations. [#12556]

• astropy.coordinates.Distance constructor no longer ignores the unit keyword when parallax is provided. [#12569]

astropy.cosmology

• astropy.cosmology.utils.aszarr can now convert Column objects. [#12525]

• Reading a cosmology from an ECSV will load redshift and Hubble parameter units from the cosmology units module. [#12636]

astropy.io.fits

• Fix formatting issue in _dump_coldefs and add tests for tabledump and tableload convenience functions. [#12526]

astropy.io.misc

• YAML can now also represent quantities and arrays with structured dtype, as well as structured scalars based on np.void. [#12509]

astropy.modeling

• Fixes error when fitting multiplication or division based compound models where the sub-models have different output units. [#12475]

• Bugfix for incorrectly initialized and filled parameters data for Spline1D model. [#12523]

• Bugfix for keyerror thrown by Model.input_units_equivalencies when used on fix_inputs models which have no set unit equivalencies. [#12597]

astropy.table

• astropy.table.Table.keep_columns() and astropy.table.Table.remove_columns() now work with generators of column names. [#12529]

• Avoid duplicate storage of info in serialized columns if the column used to serialize already can hold that information. [#12607]

astropy.timeseries

• Fixed edge case bugs which emerged when using aggregate_downsample with custom bins. [#12527]

astropy.units

• Structured units can be serialized to/from yaml. [#12492]

• Fix bad typing problems by removing interaction with NDArray.__class_getitem__. [#12511]

• Ensure that Quantity.to_string(format='latex') properly typesets exponents also when u.quantity.conf.latex_array_threshold = -1 (i.e., when the threshold is taken from numpy). [#12573]

• Structured units can now be copied with copy.copy and copy.deepcopy and also pickled and unpicked also for protocol >= 2. This does not work for big-endian architecture with older numpy<1.21.1. [#12583]

astropy.utils

• Ensure that a Masked instance can be used to initialize (or viewed as) a numpy.ma.Maskedarray. [#12482]

• Ensure Masked also works with numpy >=1.22, which has a keyword argument name change for np.quantile. [#12511]

• astropy.utils.iers.LeapSeconds.auto_open() no longer emits unnecessary warnings when astropy.utils.iers.conf.auto_max_age is set to None. [#12713]

Version 5.0 (2021-11-15)

New Features

astropy.convolution

• Added dealiasing support to convolve_fft. [#11495]

astropy.coordinates

• Added missing coordinate transformations where the starting and ending frames are the same (i.e., loopback transformations). [#10909]

• Allow negation, multiplication and division also of representations that include a differential (e.g., SphericalRepresentation with a SphericalCosLatDifferential). For all operations, the outcome is equivalent to transforming the representation and differential to cartesian, then operating on those, and transforming back to the original representation (except for UnitSphericalRepresentation, which will return a SphericalRepresentation if there is a scale change). [#11470]

• RadialRepresentation.transform can work with a multiplication matrix only. All other matrices still raise an exception. [#11576]

• transform methods are added to BaseDifferential and CartesianDifferential. All transform methods on Representations now delegate transforming differentials to the differential objects. [#11654]

• Adds new HADec built-in frame with transformations to/from ICRS and CIRS. This frame complements AltAz to give observed coordinates (hour angle and declination) in the ITRS for an equatorially mounted telescope. [#11676]

• SkyCoord objects now have a to_table() method, which allows them to be converted to a QTable. [#11743]

astropy.cosmology

• Cosmologies now store metadata in a mutable parameter meta. The initialization arguments name and meta are keyword-only. [#11542]

• A new unit, redshift, is defined. It is a dimensionless unit to distinguish redshift quantities from other non-redshift values. For compatibility with dimensionless quantities the equivalency dimensionless_redshift is added. This equivalency is enabled by default. [#11786]

• Add equality operator for comparing Cosmology instances. Comparison is done on all immutable fields (this excludes ‘meta’).

  Now the following will work:

  >>> from astropy.cosmology import Planck13, Planck18
  >>> Planck13 == Planck18
  False
  
  >>> Planck18 == Planck18
  True [#11813]
  

• Added read/write methods to Cosmology using the Unified I/O registry. Now custom file format readers, writers, and format-identifier functions can be registered to read, write, and identify, respectively, Cosmology objects. Details are discussed in an addition to the docs. [#11948]

• Added to_format/from_format methods to Cosmology using the Unified I/O registry. Now custom format converters and format-identifier functions can be registered to transform Cosmology objects. The transformation between Cosmology and dictionaries is pre-registered. Details are discussed in an addition to the docs. [#11998]

• Added units module for defining and collecting cosmological units and equivalencies. [#12092]

• Flat cosmologies are now set by a mixin class, FlatCosmologyMixin and its FLRW-specific subclass FlatFLRWMixin. All FlatCosmologyMixin are flat, but not all flat cosmologies are instances of FlatCosmologyMixin. As example, LambdaCDM may be flat (for the a specific set of parameter values), but FlatLambdaCDM will be flat.

  Cosmology parameters are now descriptors. When accessed from a class they transparently stores information, like the units and accepted equivalencies. On a cosmology instance, the descriptor will return the parameter value. Parameters can have custom getter methods.

  Cosmological equality is refactored to check Parameters (and the name) A new method, is_equivalent, is added to check Cosmology equivalence, so a FlatLambdaCDM and flat LambdaCDM are equivalent. [#12136]

• Replaced z = np.asarray(z) with z = u.Quantity(z, u.dimensionless_unscaled).value in Cosmology methods. Input of values with incorrect units raises a UnitConversionError or TypeError. [#12145]

• Cosmology Parameters allow for custom value setters. Values can be set once, but will error if set a second time. If not specified, the default setter is used, which will assign units using the Parameters units and equivalencies (if present). Alternate setters may be registered with Parameter to be specified by a str, not a decorator on the Cosmology. [#12190]

• Cosmology instance conversion to dict now accepts keyword argument cls to determine dict type, e.g. OrderedDict. [#12209]

• A new equivalency is added between redshift and the Hubble parameter and values with units of little-h. This equivalency is also available in the catch-all equivalency with_redshift. [#12211]

• A new equivalency is added between redshift and distance – comoving, lookback, and luminosity. This equivalency is also available in the catch-all equivalency with_redshift. [#12212]

• Register Astropy Table into Cosmology’s to/from_format I/O, allowing a Cosmology instance to be parsed from or converted to a Table instance. Also adds the __astropy_table__ method allowing Table(cosmology). [#12213]

• The WMAP1 and WMAP3 are accessible as builtin cosmologies. [#12248]

• Register Astropy Model into Cosmology’s to/from_format I/O, allowing a Cosmology instance to be parsed from or converted to a Model instance. [#12269]

• Register an ECSV reader and writer into Cosmology’s I/O, allowing a Cosmology instance to be read from from or written to an ECSV file. [#12321]

astropy.io.ascii

• Added new way to specify the dtype for tables that are read: converters can specify column names with wildcards. [#11892]

• Added a new astropy.io.ascii.Mrt class to write tables in the American Astronomical Society Machine-Readable Table format, including documentation and tests for the same. [#11897, #12301, #12302]

• When writing, the input data are no longer copied, improving performance. Metadata that might be changed, such as format and serialization information, is copied, hence users can continue to count on no changes being made to the input data. [#11919]

astropy.io.misc

• Add Parquet serialization of Tables with pyarrow, including metadata support and columnar access. [#12215]

astropy.modeling

• Added fittable spline models to modeling. [#11634]

• Extensive refactor of BoundingBox for better usability and maintainability. [#11930]

• Added CompoundBoundingBox feature to ~astropy.modeling, which allows more flexibility in defining bounding boxes for models that are applied to images with many slices. [#11942]

• Improved parameter support for astropy.modeling.core.custom_model created models. [#11984]

• Added the following trigonometric models and linked them to their appropriate inverse models:

  • Cosine1D [#12158]

  • Tangent1D

  • ArcSine1D

  • ArcCosine1D

  • ArcTangent1D [#12185]

astropy.table

• Added a new method Table.update() which does a dictionary-style update of a Table by adding or replacing columns. [#11904]

• Masked quantities are now fully supported in tables. This includes QTable automatically converting MaskedColumn instances to MaskedQuantity, and Table doing the reverse. [#11914]

• Added new keyword arguments keys_left and keys_right to the table join function to support joining tables on key columns with different names. In addition the new keywords can accept a list of column-like objects which are used as the match keys. This allows joining on arbitrary data which are not part of the tables being joined. [#11954]

• Formatting of any numerical values in the output of Table.info() and Column.info() has been improved. [#12022]

• It is now possible to add dask arrays as columns in tables and have them remain as dask arrays rather than be converted to Numpy arrays. [#12219]

• Added a new registry for mixin handlers, which can be used to automatically convert array-like Python objects into mixin columns when assigned to a table column. [#12219]

astropy.time

• Adds a new method earth_rotation_angle to calculate the Local Earth Rotation Angle. Also adjusts Local Sidereal Time for the Terrestrial Intermediate Origin (TIO) and adds a rigorous correction for polar motion. The TIO adjustment is approximately 3 microseconds per century from J2000 and the polar motion correction is at most about +/-50 nanoseconds. For models IAU1982 and IAU1994, no such adjustments are made as they pre-date the TIO concept. [#11680]

astropy.timeseries

• A custom binning scheme is now available in aggregate_downsample. It allows time_bin_start and time_bin_size to be arrays, and adds an optional time_bin_end. This scheme mirrors the API for BinnedTimeSeries. [#11266]

astropy.units

• Quantity gains a __class_getitem__ to create unit-aware annotations

  with the syntax Quantity[unit or physical_type, shape, numpy.dtype]. If the python version is 3.9+ or typing_extensions is installed, these are valid static type annotations. [#10662]

• Each physical type is added to astropy.units.physical (e.g., physical.length or physical.electrical_charge_ESU). The attribute-accessible names (underscored, without parenthesis) also work with astropy.units.physical.get_physical_type. [#11691]

• It is now possible to have quantities based on structured arrays in which the unit has matching structure, giving each field its own unit, using units constructed like Unit('AU,AU/day'). [#11775]

• The milli- prefix has been added to astropy.units.Angstrom. [#11788]

• Added attributes base, coords, and index and method copy() to QuantityIterator to match numpy.ndarray.flatiter. [#11796]

• Added “angular frequency” and “angular velocity” as aliases for the “angular speed” physical type. [#11865]

• Add light-second to units of length [#12128]

astropy.utils

• The astropy.utils.deprecated_renamed_argument() decorator now supports custom warning messages. [#12305]

• The NaN-aware numpy functions such as np.nansum now work on Masked arrays, with masked values being treated as NaN, but without raising warnings or exceptions. [#12454]

astropy.visualization

• Added a feature so that SphericalCircle will accept center parameter as a SkyCoord object. [#11790]

astropy.wcs

• astropy.wcs.utils.obsgeo_to_frame has been added to convert the obsgeo coordinate array on astropy.wcs.WCS objects to an ITRS coordinate frame instance. [#11716]

• Updated bundled WCSLIB to version 7.7 with several bugfixes. [#12034]

API Changes

astropy.config

• update_default_config and ConfigurationMissingWarning are deprecated. [#11502]

astropy.constants

• Removed deprecated astropy.constants.set_enabled_constants context manager. [#12105]

astropy.coordinates

• Positions for the Moon using the ‘builtin’ ephemeris now use the new erfa.moon98 function instead of our own implementation of the Meeus algorithm. As this also corrects a misunderstanding of the frame returned by the Meeus, this improves the agreement with the JPL ephemeris from about 30 to about 6 km rms. [#11753]

• Removed deprecated representation attribute from astropy.coordinates.BaseCoordinateFrame class. [#12257]

• SpectralQuantity and SpectralCoord .to_value method can now be called without unit argument in order to maintain a consistent interface with Quantity.to_value [#12440]

astropy.cosmology

• z_at_value now works with arrays for all arguments (except func, verbose, and method). Consequently, coordinates.Distance.z can be used when Distance is an array. [#11778]

• Remove deprecation warning and error remapping in Cosmology.clone. Now unknown arguments will raise a TypeError, not an AttributeError. [#11785]

• The read/write and to/from_format Unified I/O registries are separated and apply only to Cosmology. [#12015]

• Cosmology parameters in cosmology.parameters.py now have units, where applicable. [#12116]

• The function astropy.cosmology.utils.inf_like() is deprecated. [#12175]

• The function astropy.cosmology.utils.vectorize_if_needed() is deprecated. A new function astropy.cosmology.utils.vectorize_redshift_method() is added as replacement. [#12176]

• Cosmology base class constructor now only accepts arguments name and meta. Subclasses should add relevant arguments and not pass them to the base class. [#12191]

astropy.io

• When astropy raises an OSError because a file it was told to write already exists, the error message now always suggests the use of the overwrite=True argument. The wording is now consistent for all I/O formats. [#12179]

astropy.io.ascii

• Removed deprecated overwrite=None option for astropy.io.ascii.ui.write(). Overwriting existing files now only happens if overwrite=True. [#12171]

astropy.io.fits

• The internal class _CardAccessor is no longer registered as a subclass of the Sequence or Mapping ABCs. [#11923]

• The deprecated clobber argument will be removed from the astropy.io.fits functions in version 5.1, and the deprecation warnings now announce that too. [#12311]

astropy.io.registry

• The write function now is allowed to return possible content results, which means that custom writers could, for example, create and return an instance of some container class rather than a file on disk. [#11916]

• The registry functions are refactored into a class-based system. New Read-only, write-only, and read/write registries can be created. All functions accept a new argument registry, which if not specified, defaults to the global default registry. [#12015]

astropy.io.votable

• Deprecated the pedantic keyword argument in the astropy.io.votable.table.parse function and the corresponding configuration setting. It has been replaced by the verify option. [#12129]

astropy.modeling

• Refactored how astropy.modeling.Model handles model evaluation in order to better organize the code. [#11931]

• Removed the following deprecated modeling features:

  astropy.modeling.utils.ExpressionTree class, astropy.modeling.functional_models.MexicanHat1D model, astropy.modeling.functional_models.MexicanHat2D model, astropy.modeling.core.Model.inputs setting in model initialize, astropy.modeling.core.CompoundModel.inverse setting in model initialize, and astropy.modeling.core.CompoundModel.both_inverses_exist() method. [#11978]

• Deprecated the AliasDict class in modeling.utils. [#12411]

astropy.nddata

• Removed block_reduce and block_replicate functions from nddata.utils. These deprecated functions in nddata.utils were moved to nddata.blocks. [#12288]

astropy.stats

• Removed the following deprecated features from astropy.stats:

  • conf argument for funcs.binom_conf_interval() and funcs.binned_binom_proportion(),

  • conflevel argument for funcs.poisson_conf_interval(), and

  • conf_lvl argument for jackknife.jackknife_stats(). [#12200]

astropy.table

• Printing a Table now shows the qualified class name of mixin columns in the dtype header row instead of “object”. This applies to all the Table formatted output methods whenever show_dtype=True is selected. [#11660]

• The ‘overwrite’ argument has been added to the jsviewer table writer. Overwriting an existing file requires ‘overwrite’ to be True. [#11853]

• The ‘overwrite’ argument has been added to the pandas table writers. Overwriting an existing file requires ‘overwrite’ to be True. [#11854]

• The table join function now accepts only the first four arguments left, right, keys, and join_type as positional arguments. All other arguments must be supplied as keyword arguments. [#11954]

• Adding a dask array to a Table will no longer convert that dask to a Numpy array, so accessing t[‘dask_column’] will now return a dask array instead of a Numpy array. [#12219]

astropy.time

• Along with the new method earth_rotation_angle, sidereal_time now accepts an EarthLocation as the longitude argument. [#11680]

astropy.units

• Unit littleh and equivalency with_H0 have been moved to the cosmology module and are deprecated from astropy.units. [#12092]

astropy.utils

• astropy.utils.introspection.minversion() now uses importlib.metadata.version(). Therefore, its version_path keyword is no longer used and deprecated. This keyword will be removed in a future release. [#11714]

• Updated utils.console.Spinner to better resemble the API of utils.console.ProgressBar, including an update() method and iterator support. [#11772]

• Removed deprecated check_hashes in check_download_cache(). The function also no longer returns anything. [#12293]

• Removed unused download_cache_lock_attempts configuration item in astropy.utils.data. Deprecation was not possible. [#12293]

• Removed deprecated hexdigest keyword from import_file_to_cache(). [#12293]

• Setting remote_timeout configuration item in astropy.utils.data to 0 will no longer disable download from the Internet; Set allow_internet configuration item to False instead. [#12293]

astropy.visualization

• Removed deprecated imshow_only_kwargs keyword from imshow_norm. [#12290]

astropy.wcs

• Move complex logic from HighLevelWCSMixin.pixel_to_world and HighLevelWCSMixin.world_to_pixel into the helper functions astropy.wcs.wcsapi.high_level_api.high_level_objects_to_values and astropy.wcs.wcsapi.high_level_api.values_to_high_level_objects to allow reuse in other places. [#11950]

Bug Fixes

astropy.config

• generate_config no longer outputs wrong syntax for list type. [#12037]

astropy.constants

• Fixed a bug where an older constants version cannot be set directly after astropy import. [#12084]

astropy.convolution

• Passing an array argument for any Kernel1D or Kernel2D subclasses (with the exception of CustomKernel) will now raise a TypeError. [#11969]

astropy.coordinates

• If a Table containing a SkyCoord object as a column is written to a FITS, ECSV or HDF5 file then any velocity information that might be present will be retained. [#11750]

• The output of SkyCoord.apply_space_motion() now always has the same differential type as the SkyCoord itself. [#11932]

• Fixed bug where Angle, Latitude and Longitude with NaN values could not be printed. [#11943]

• Fixed a bug with the transformation from PrecessedGeocentric to GCRS where changes in obstime, obsgeoloc, or obsgeovel were ignored. This bug would also affect loopback transformations from one PrecessedGeocentric frame to another PrecessedGeocentric frame. [#12152]

• Fixed a bug with the transformations between TEME and ITRS or between TEME and itself where a change in obstime was ignored. [#12152]

• Avoid unnecessary transforms through CIRS for AltAz and HADec and use ICRS as intermediate frame for these transformations instead. [#12203]

• Fixed a bug where instantiating a representation with a longitude component could mutate input provided for that component even when copying is specified. [#12307]

• Wrapping an Angle array will now ignore NaN values instead of attempting to wrap them, which would produce unexpected warnings/errors when working with coordinates and representations due to internal broadcasting. [#12317]

astropy.cosmology

• Dictionaries for in-built cosmology realizations are not altered by creating the realization and are also made immutable. [#12278]

astropy.io.fits

• Prevent zero-byte writes for FITS binary tables to speed up writes on the Lustre filesystem. [#11955]

• Enable json.dump for FITS_rec with variable length (VLF) arrays. [#11957]

• Add support for reading and writing int8 images [#11996]

• Ensure header passed to astropy.io.fits.CompImageHDU does not need to contain standard cards that can be automatically generated, such as BITPIX and NAXIS. [#12061]

• Fixed a bug where astropy.io.fits.HDUDiff would ignore the ignore_blank_cards keyword argument. [#12122]

• Open uncompressed file even if extension says it’s compressed [#12135]

• Fix the computation of the DATASUM in a CompImageHDU when the data is >1D. [#12138]

• Reading files where the SIMPLE card is present but with an invalid format now issues a warning instead of raising an exception [#12234]

• Convert UNDEFINED to None when iterating over card values. [#12310]

astropy.io.misc

• Update ASDF tag versions in ExtensionType subclasses to match ASDF Standard 1.5.0. [#11986]

• Fix ASDF serialization of model inputs and outputs and add relevant assertion to test helper. [#12381]

• Fix bug preventing ASDF serialization of bounding box for models with only one input. [#12385]

astropy.io.votable

• Now accepting UCDs containing phot.color. [#11982]

astropy.modeling

• Added Parameter descriptions to the implemented models which were missing. [#11232]

• The separable property is now correctly set on models constructed with astropy.modeling.custom_model. [#11744]

• Minor bugfixes and improvements to modeling including the following:

  • Fixed typos and clarified several errors and their messages throughout modeling.

  • Removed incorrect try/except blocks around scipy code in convolution.py and functional_models.py.

  • Fixed Ring2D model’s init to properly accept all combinations of r_in, r_out, and width.

  • Fixed bug in tau validator for the Logarithmic1D and Exponential1D models when using them as model sets.

  • Fixed copy method for Parameter in order to prevent an automatic KeyError, and fixed bool for Parameter so that it functions with vector values.

  • Removed unreachable code from Parameter, the _Tabular model, and the Drude1D model.

  • Fixed validators in Drude1D model so that it functions in a model set.

  • Removed duplicated code from polynomial.py for handing of domain and window.

  • Fixed the Pix2Sky_HEALPixPolar and Sky2Pix_HEALPixPolar modes so that their evaluate and inverse methods actually work without raising an error. [#12232]

astropy.nddata

• Ensure that the wcs= argument to NDData is always parsed into a high level WCS object. [#11985]

astropy.stats

• Fixed a bug in sigma clipping where the bounds would not be returned for completely empty or masked data. [#11994]

• Fixed a bug in biweight_midvariance and biweight_scale where output data units would be dropped for constant data and where the result was a scalar NaN. [#12146]

astropy.table

• Ensured that MaskedColumn.info is propagated in all cases, so that when tables are sliced, writing will still be as requested on info.serialize_method. [#11917]

• table.conf.replace_warnings and table.jsviewer.conf.css_urls configuration items now have correct 'string_list' type. [#12037]

• Fixed an issue where initializing from a list of dict-like rows (Mappings) did not work unless the row values were instances of dict. Now any object that is an instance of the more general collections.abc.Mapping will work. [#12417]

astropy.uncertainty

• Ensure that scalar QuantityDistribution unit conversion in ufuncs works properly again. [#12471]

astropy.units

• Add quantity support for scipy.special dimensionless functions erfinv, erfcinv, gammaln and loggamma. [#10934]

• VOUnit.to_string output is now compliant with IVOA VOUnits 1.0 standards. [#11565]

• Units initialization with unicode has been expanded to include strings such as ‘M☉’ and ‘e⁻’. [#11827]

• Give a more informative NotImplementedError when trying to parse a unit using an output-only format such as ‘unicode’ or ‘latex’. [#11829]

astropy.utils

• Fixed a bug in get_readable_fileobj that prevented the unified file read interface from closing ASCII files. [#11809]

• The function astropy.utils.decorators.deprecated_attribute() no longer ignores its message, alternative, and pending arguments. [#12184]

• Ensure that when taking the minimum or maximum of a Masked array, any masked NaN values are ignored. [#12454]

astropy.visualization

• The tick labelling for radians has been fixed to remove a redundant .0 in the label for integer multiples of pi at 2pi and above. [#12221]

• Fix a bug where non-astropy.wcs.WCS WCS instances were not accepted in WCSAxes.get_transform. [#12286]

• Fix compatibility with Matplotlib 3.5 when using the grid_type='contours' mode for drawing grid lines. [#12447]

astropy.wcs

• Enabled SlicedLowLevelWCS.pixel_to_world_values to handle slices including non-int integers, e.g. numpy.int64. [#11980]

Other Changes and Additions

• In docstrings, Sphinx cross-reference targets now use intersphinx, even if the target is an internal link (link is now 'astropy:link). When built in Astropy these links are interpreted as internal links. When built in affiliate packages, the link target is set by the key ‘astropy’ in the intersphinx mapping. [#11690]

• Made PyYaml >= 3.13 a strict runtime dependency. [#11903]

• Minimum version of required Python is now 3.8. [#11934]

• Minimum version of required Scipy is now 1.3. [#11934]

• Minimum version of required Matplotlib is now 3.1. [#11934]

• Minimum version of required Numpy is now 1.18. [#11935]

• Fix deprecation warnings with Python 3.10 [#11962]

• Speed up minversion() in cases where a module with a __version__ attribute is passed. [#12174]

• astropy now requires packaging. [#12199]

• Updated the bundled CFITSIO library to 4.0.0. When compiling with an external library, version 3.35 or later is required. [#12272]

Version 4.3.1 (2021-08-11)

Bug Fixes

astropy.io.fits

• In fits.io.getdata do not fall back to first non-primary extension when user explicitly specifies an extension. [#11860]

• Ensure multidimensional masked columns round-trip properly to FITS. [#11911]

• Ensure masked times round-trip to FITS, even if multi-dimensional. [#11913]

• Raise ValueError if an np.float32 NaN/Inf value is assigned to a header keyword. [#11922]

astropy.modeling

• Fixed bug in fix_inputs handling of bounding boxes. [#11908]

astropy.table

• Fix an error when converting to pandas any Table subclass that automatically adds a table index when the table is created. An example is a binned TimeSeries table. [#12018]

astropy.units

• Ensure that unpickling quantities and units in new sessions does not change hashes and thus cause problems with (de)composition such as getting different answers from the .si attribute. [#11879]

• Fixed cannot import name imperial from astropy.units namespace. [#11977]

astropy.utils

• Ensure any .info on Masked instances is propagated correctly when viewing or slicing. As a consequence, MaskedQuantity can now be correctly written to, e.g., ECSV format with serialize_method='data_mask'. [#11910]

Version 4.3 (2021-07-26)

New Features

astropy.convolution

• Change padding sizes for fft_pad in convolve_fft from powers of 2 only to scipy-optimized numbers, applied separately to each dimension; yielding some performance gains and avoiding potential large memory impact for certain multi-dimensional inputs. [#11533]

astropy.coordinates

• Adds the ability to create topocentric CIRS frames. Using these, AltAz calculations are now accurate down to the milli-arcsecond level. [#10994]

• Adds a direct transformation from ICRS to AltAz frames. This provides a modest speedup of approximately 10 percent. [#11079]

• Adds new WGS84GeodeticRepresentation, WGS72GeodeticRepresentation, and GRS80GeodeticRepresentation. These are mostly for use inside EarthLocation but can also be used to convert between geocentric (cartesian) and different geodetic representations directly. [#11086]

• SkyCoord.guess_from_table now also searches for differentials in the table. In addition, multiple regex matches can be resolved when they are exact component names, e.g. having both columns “dec” and “pm_dec” no longer errors and will be included in the SkyCoord. [#11417]

• All representations now have a transform method, which allows them to be transformed by a 3x3 matrix in a Cartesian basis. By default, transformations are routed through CartesianRepresentation. SphericalRepresentation and PhysicssphericalRepresentation override this for speed and to prevent NaN leakage from the distance to the angular components. Also, the functions is_O3 and is_rotation have been added to matrix_utities for checking whether a matrix is in the O(3) group or is a rotation (proper or improper), respectively. [#11444]

• Moved angle formatting and parsing utilities to astropy.coordinates.angle_formats. Added new functionality to astropy.coordinates.angle_utilities for generating points on or in spherical surfaces, either randomly or on a grid. [#11628]

• Added a new method to SkyCoord, spherical_offsets_by(), which is the conceptual inverse of spherical_offsets_to(): Given angular offsets in longitude and latitude, this method returns a new coordinate with the offsets applied. [#11635]

• Refactor conversions between GCRS and CIRS,TETE for better accuracy and substantially improved speed. [#11069]

• Also refactor EarthLocation.get_gcrs for an increase in performance of an order of magnitude, which enters as well in getting observed positions of planets using get_body. [#11073]

• Refactored the usage of metaclasses in astropy.coordinates to instead use __init_subclass__ where possible. [#11090]

• Removed duplicate calls to `transform_to` from `match_to_catalog_sky` and `match_to_catalog_3d`, improving their performance. [#11449]

• The new DE440 and DE440s ephemerides are now available via shortcuts ‘de440’ and ‘de440s’. The DE 440s ephemeris will probably become the default ephemeris when choosing ‘jpl’ in 5.0. [#11601]

astropy.cosmology

• Cosmology parameter dictionaries now also specify the Cosmology class to which the parameters correspond. For example, the dictionary for astropy.cosmology.parameters.Planck18 has the added key-value pair (“cosmology”, “FlatLambdaCDM”). [#11530]

astropy.io.ascii

• Added support for reading and writing ASCII tables in QDP (Quick and Dandy Plotter) format. [#11256]

• Added support for reading and writing multidimensional column data (masked and unmasked) to ECSV. Also added formal support for reading and writing object-type column data which can contain items consisting of lists, dicts, and basic scalar types. This can be used to store columns of variable-length arrays. Both of these features use JSON to convert the object to a string that is stored in the ECSV output. [#11569, #11662, #11720]

astropy.io.fits

• Added append keyword to append table objects to an existing FITS file [#2632, #11149]

• Check that the SIMPLE card is present when opening a file, to ensure that the file is a valid FITS file and raise a better error when opening a non FITS one. ignore_missing_simple can be used to skip this verification. [#10895]

• Expose Header.strip as a public method, to remove the most common structural keywords. [#11174]

• Enable the use of os.PathLike objects when dealing with (mainly FITS) files. [#11580]

astropy.io.registry

• Readers and writers can now set a priority, to assist with resolving which format to use. [#11214]

astropy.io.votable

• Version 1.4 VOTables now use the VOUnit format specification. [#11032]

• When reading VOTables using the Unified File Read/Write Interface (i.e. using the Table.read() or QTable.read() functions) it is now possible to specify all keyword arguments that are valid for astropy.io.votable.table.parse(). [#11643]

astropy.modeling

• Added a state attribute to models to allow preventing the syncing of constraint values from the constituent models. This syncing can greatly slow down fitting if there are large numbers of fit parameters. model.sync_constraints = True means check constituent model constraints for compound models every time the constraint is accessed, False, do not. Fitters that support constraints will set this to False on the model copy and then set back to True when the fit is complete before returning. [#11365]

• The convolve_models_fft function implements model convolution so that one insures that the convolution remains consistent across multiple different inputs. [#11456]

astropy.nddata

• Prevent unnecessary copies of the data during NDData arithmetic when units need to be added. [#11107]

• NDData str representations now show units, if present. [#11553]

astropy.stats

• Added the ability to specify stdfunc=’mad_std’ when doing sigma clipping, which will use a built-in function and lead to significant performance improvements if cenfunc is ‘mean’ or ‘median’. [#11664]

• Significantly improved the performance of sigma clipping when cenfunc and stdfunc are passed as strings and the grow option is not used. [#11219]

• Improved performance of bayesian_blocks() by removing one np.log() call [#11356]

astropy.table

• Add table attributes to include or exclude columns from the output when printing a table. This functionality includes a context manager to include/exclude columns temporarily. [#11190]

• Improved the string representation of objects related to Table.indices so they now indicate the object type and relevant attributes. [#11333]

astropy.timeseries

• An exception is raised when n_bins is passed as an argument while any of the parameters time_bin_start or time_bin_size is not scalar. [#11463]

astropy.units

• The physical_type attributes of each unit are now objects of the (new) astropy.units.physical.PhysicalType class instead of strings and the function astropy.units.physical.get_physical_type can now translate strings to these objects. [#11204]

• The function astropy.units.physical.def_physical_type was created to either define entirely new physical types, or to add more physical type names to an existing physical types. [#11204]

• PhysicalType’s can be operated on using operations multiplication, division, and exponentiation are to facilitate dimensional analysis. [#11204]

• It is now possible to define aliases for units using astropy.units.set_enabled_aliases. This can be used when reading files that have misspelled units. [#11258]

• Add a new “DN” unit, units.dn or units.DN, representing data number for a detector. [#11591]

astropy.utils

• Added ssl_context and allow_insecure options to download_file, as well as the ability to optionally use the certifi package to provide root CA certificates when downloading from sites secured with TLS/SSL. [#10434]

• astropy.utils.data.get_pkg_data_path is publicly scoped (previously the private function _find_pkg_data_path) for obtaining file paths without checking if the file/directory exists, as long as the package and module do. [#11006]

• Deprecated astropy.utils.OrderedDescriptor and astropy.utils.OrderedDescriptorContainer, as new features in Python 3 make their use less compelling. [#11094, #11099]

• astropy.utils.masked provides a new Masked class/factory that can be used to represent masked ndarray and all its subclasses, including Quantity and its subclasses. These classes can be used inside coordinates, but the mask is not yet exposed. Generally, the interface should be considered experimental. [#11127, #11792]

• Add new utils.parsing module to with helper wrappers around ply. [#11227]

• Change the Time and IERS leap second handling so that the leap second table is updated only when a Time transform involving UTC is performed. Previously this update check was done the first time a Time object was created, which in practice occurred when importing common astropy subpackages like astropy.coordinates. Now you can prevent querying internet resources (for instance on a cluster) by setting iers.conf.auto_download = False. This can be done after importing astropy but prior to performing any Time scale transformations related to UTC. [#11638]

• Added a new module at astropy.utils.compat.optional_deps to consolidate the definition of HAS_x optional dependency flag variables, like HAS_SCIPY. [#11490]

astropy.wcs

• Add IVOA UCD mappings for some FITS WCS keywords commonly used in solar physics. [#10965]

• Add STOKES FITS WCS keyword to the IVOA UCD mapping. [#11236]

• Updated bundled version of WCSLIB to version 7.6. See https://www.atnf.csiro.au/people/mcalabre/WCS/CHANGES for a list of included changes. [#11549]

API Changes

astropy.coordinates

• For input to representations, subclasses of the class required for a given attribute will now be allowed in. [#11113]

• Except for UnitSphericalRepresentation, shortcuts in representations now allow for attached differentials. [#11467]

• Allow coordinate name strings as input to SkyCoord.is_transformable_to. [#11552]

astropy.cosmology

• Change z_at_value to use scipy.optimize.minimize_scalar with default method Brent (other options Bounded and Golden) and accept bracket option to set initial search region. [#11080]

• Clarified definition of inputs to angular_diameter_distance_z1z2. The function now emits AstropyUserWarning when z2 is less than z1. [#11197]

• Split cosmology realizations from core classes, moving the former to new file realizations. [#11345]

• Since cosmologies are immutable, the initialization signature and values can be stored, greatly simplifying cloning logic and extending it to user-defined cosmology classes that do not have attributes with the same name as each initialization argument. [#11515]

• Cloning a cosmology with changed parameter(s) now appends “(modified)” to the new instance’s name, unless a name is explicitly passed to clone. [#11536]

• Allow m_nu to be input as any quantity-like or array-like – Quantity, array, float, str, etc. Input is passed to the Quantity constructor and converted to eV, still with the prior mass-energy equivalence enabled. [#11640]

astropy.io.fits

• For conversion between FITS tables and astropy Table, the standard mask values of NaN for float and null string for string are now properly recognized, leading to a MaskedColumn with appropriately set mask instead of a Column with those values exposed. Conversely, when writing an astropy Table to a FITS tables, masked values are now consistently converted to the standard FITS mask values of NaN for float and null string for string (i.e., not just for tables with masked=True, which no longer is guaranteed to signal the presence of MaskedColumn). [#11222]

astropy.io.votable

• The use of version='1.0' is now fully deprecated in constructing a astropy.io.votable.tree.VOTableFile. [#11659]

astropy.modeling

• Removed deprecated astropy.modeling.blackbody module. [#10972]

astropy.table

• Added Column.value as an alias for the existing Column.data attribute. This makes accessing a column’s underlying data array consistent with the .value attribute available for Time and Quantity objects. [#10962]

• In reading from a FITS tables, the standard mask values of NaN for float and null string for string are properly recognized, leading to a MaskedColumn with appropriately set mask. [#11222]

• Changed the implementation of the table.index.Index class so instantiating from this class now returns an Index object as expected instead of a SlicedIndex object. [#11333]

astropy.units

• The physical_type attribute of units now returns an instance of astropy.units.physical.PhysicalType instead of a string. Because PhysicalType instances can be compared to strings, no code changes should be necessary when making comparisons. The string representations of different physical types will differ from previous releases. [#11204]

• Calling Unit() with no argument now returns a dimensionless unit, as was documented but not implemented. [#11295]

astropy.utils

• Removed deprecated utils.misc.InheritDocstrings and utils.timer. [#10281]

• Removed usage of deprecated ipython stream in utils.console. [#10942]

astropy.wcs

• Deprecate accuracy argument in all_world2pix which was mistakenly documented, in the case accuracy was ever used. [#11055]

Bug Fixes

astropy.convolution

• Fixes for convolve_fft documentation examples. [#11510]

astropy.coordinates

• Allow Distance instances with negative distance values as input for SphericalRepresentation. This was always noted as allowed in an exception message when a negative Quantity with length units was passed in, but was not actually possible to do. [#11113]

• Makes the Angle.to_string method to follow the format described in the docstring with up to 8 significant decimals instead of 4. [#11153]

• Ensure that proper motions can be calculated when converting a SkyCoord with cartesian representation to unit-spherical, by fixing the conversion of CartesianDifferential to UnitSphericalDifferential. [#11469]

• When re-representing coordinates from spherical to unit-spherical and vice versa, the type of differential will now be preserved. For instance, if only a radial velocity was present, that will remain the case (previously, a zero proper motion component was added). [#11482]

• Ensure that wrapping of Angle does not raise a warning even if nan are present. Also try to make sure that the result is within the wrapped range even in the presence of rounding errors. [#11568]

• Comparing a non-SkyCoord object to a SkyCoord using == no longer raises an error. [#11666]

• Different SkyOffsetFrame classes no longer interfere with each other, causing difficult to debug problems with the origin attribute. The origin attribute now no longer is propagated, so while it remains available on a SkyCoord that is an offset, it no longer is available once that coordinate is transformed to another frame. [#11730] [#11730]

astropy.cosmology

• Cosmology instance names are now immutable. [#11535]

astropy.io.ascii

• Fixed bug where writing a table that has comments defined (via tbl.meta['comments']) with the ‘csv’ format was failing. Since the formally defined CSV format does not support comments, the comments are now just ignored unless comment=<comment prefix> is supplied to the write() call. [#11475]

• Fixed the issue where the CDS reader failed to treat columns as nullable if the ReadMe file contains a limits specifier. [#11531]

• Made sure that the CDS reader does not ignore an order specifier that may be present after the null specifier ‘?’. Also made sure that it checks null values only when an ‘=’ symbol is present and reads description text even if there is no whitespace after ‘?’. [#11593]

astropy.io.fits

• Fix ColDefs.add_col/del_col to allow in-place addition or removal of a column. [#11338]

• Fix indexing of fits.Header with Numpy integers. [#11387]

• Do not delete EXTNAME for compressed image header if a default and non-default EXTNAME are present. [#11396]

• Prevent warnings about HIERARCH with CompImageHeader class. [#11404]

• Fixed regression introduced in Astropy 4.0.5 and 4.2.1 with verification of FITS headers with HISTORY or COMMENT cards with long (> 72 characters) values. [#11487]

• Fix reading variable-length arrays when there is a gap between the data and the heap. [#11688]

astropy.io.votable

• NumericArray converter now properly broadcasts scalar mask to array. [#11157]

• VOTables are now written with the correct namespace and schema location attributes. [#11659]

astropy.modeling

• Fixes the improper propagation of bounding_box from astropy.modeling.models to their inverses. For cases in which the inverses bounding_box can be determined, the proper calculation has been implemented. [#11414]

• Bugfix to allow rotation models to accept arbitrarily-shaped inputs. [#11435]

• Bugfixes for astropy.modeling to allow fix_inputs to accept empty dictionaries and dictionaries with numpy integer keys. [#11443]

• Bugfix for how SPECIAL_OPERATORS are handled. [#11512]

• Fixes Model crashes when some inputs are scalars and during some types of output reshaping. [#11548]

• Fixed bug in LevMarLSQFitter when using weights and vector inputs. [#11603]

astropy.stats

• Fixed a bug with the copy=False option when carrying out sigma clipping - previously if masked=False this still copied the data, but this will now change the array in-place. [#11219]

astropy.table

• Ensure that adding a Quantity or other mixin column to a Table does not have side effects, such as creating an associated info instance (which would lead to slow-down of, e.g., slicing afterwards). [#11077]

• When writing to a FITS tables, masked values are again always converted to the standard FITS mask values of NaN for float and null string for string, not just for table with masked=True. [#11222]

• Using Table.to_pandas() on an indexed Table with masked integer values now correctly construct the pandas.DataFrame. [#11432]

• Fixed Table HTML representation in Jupyter notebooks so that it is horizontally scrollable within Visual Studio Code. This was done by wrapping the <table> in a <div> element. [#11476]

• Fix a bug where a string-valued Column that happened to have a unit attribute could not be added to a QTable. Such columns are now simply kept as Column instances (with a warning). [#11585]

• Fix an issue in Table.to_pandas(index=<colname>) where the index column name was not being set properly for the DataFrame index. This was introduced by an API change in pandas version 1.3.0. Previously when creating a DataFrame with the index set to an astropy Column, the DataFrame index name was automatically set to the column name. [#11921]

astropy.time

• Fix a thread-safety issue with initialization of the leap-second table (which is only an issue when ERFA’s built-in table is out of date). [#11234]

• Fixed converting a zero-length time object from UTC to UT1 when an empty array is passed. [#11516]

astropy.uncertainty

• Distribution instances can now be used as input to Quantity to initialize QuantityDistribution. Hence, distribution * unit and distribution << unit will work too. [#11210]

astropy.units

• Move non-astronomy units from astrophys.py to a new misc.py file. [#11142]

• The physical type of astropy.units.mol / astropy.units.m ** 3 is now defined as molar concentration. It was previously incorrectly defined as molar volume. [#11204]

• Make ufunc helper lookup thread-safe. [#11226]

• Make Unit string parsing (as well as Angle parsing) thread-safe. [#11227]

• Decorator astropy.units.decorators.quantity_input now only evaluates return type annotations based on UnitBase or FunctionUnitBase types. Other annotations are skipped over and are not attempted to convert to the correct type. [#11506]

astropy.utils

• Make lazyproperty and classdecorator thread-safe. This should fix a number of thread safety issues. [#11224]

astropy.visualization

• Fixed a bug that resulted in some parts of grid lines being visible when they should have been hidden. [#11380]

• Fixed a bug that resulted in time_support() failing for intervals of a few months if one of the ticks was the month December. [#11615]

astropy.wcs

• fit_wcs_from_points now produces a WCS with integer NAXIXn values. [#10865]

• Updated bundled version of WCSLIB to v7.4, fixing a bug that caused the coefficients of the TPD distortion function to not be written to the header. [#11260]

• Fixed a bug in assigning type when converting colsel to numpy.ndarray. [#11431]

• Added WCSCOMPARE_* constants to the list of WCSLIB constants available/exposed through the astropy.wcs module. [#11647]

• Fix a bug that caused APE 14 WCS transformations for FITS WCS with ZOPT, BETA, VELO, VOPT, or VRAD CTYPE to not work correctly. [#11781]

Other Changes and Additions

• The configuration file is no longer created by default when importing astropy and its existence is no longer required. Affiliated packages should update their __init__.py module to remove the block using update_default_config and ConfigurationDefaultMissingWarning. [#10877]

• Replace pkg_resources (from setuptools) with importlib.metadata which comes from the stdlib, except for Python 3.7 where the backport package is added as a new dependency. [#11091]

• Turn on numpydoc’s numpydoc_xref_param_type to create cross-references for the parameter types in the Parameters, Other Parameters, Returns and Yields sections of the docstrings. [#11118]

• Docstrings across the package are standardized to enable references. Also added is an Astropy glossary-of-terms to define standard inputs, e.g. quantity-like indicates an input that can be interpreted by astropy.units.Quantity. [#11118]

• Binary wheels are now built to the manylinux2010 specification. These wheels should be supported on all versions of pip shipped with Python 3.7+. [#11377]

• The name of the default branch for the astropy git repository has been renamed to main, and the documentation and tooling has been updated accordingly. If you have made a local clone you may wish to update it following the instructions in the repository’s README. [#11379]

• Sphinx cross-reference link targets are added for every PhysicalType. Now in the parameter types in the Parameters, Other Parameters, Returns and Yields sections of the docstring, the physical type of a quantity can be annotated in square brackets. E.g. `` distance : Quantity [‘length’] `` [#11595]

• The minimum supported version of ipython is now 4.2. [#10942]

• The minimum supported version of pyerfa is now 1.7.3. [#11637]

Version 4.2.1 (2021-04-01)

Bug Fixes

astropy.cosmology

• Fixed an issue where specializations of the comoving distance calculation for certain cosmologies could not handle redshift arrays. [#10980]

astropy.io.fits

• Fix bug where manual fixes to invalid header cards were not preserved when saving a FITS file. [#11108]

astropy.io.votable

• NumericArray converter now properly broadcasts scalar mask to array. [#11157]

astropy.table

• Fix bug when initializing a Table subclass that uses TableAttribute’s. If the data were an instance of the table then attributes provided in the table initialization call could be ignored. [#11217]

astropy.time

• Change epoch of TimeUnixTAI ("unix_tai") from 1970-01-01T00:00:00 UTC to 1970-01-01T00:00:00 TAI to match the intended and documented behaviour. This essentially changes the resulting times by 8.000082 seconds, the initial offset between TAI and UTC. [#11249]

astropy.units

• Fixed a bug with the quantity_input decorator where allowing dimensionless inputs for an argument inadvertently disabled any checking of compatible units for that argument. [#11283]

astropy.utils

• Fix a bug so that np.shape, np.ndim and np.size again work on classes that use ShapedLikeNDArray, like representations, frames, sky coordinates, and times. [#11133]

astropy.wcs

• Fix error when a user defined proj_point parameter is passed to fit_wcs_from_points. [#11139]

Other Changes and Additions

• Change epoch of TimeUnixTAI ("unix_tai") from 1970-01-01T00:00:00 UTC to 1970-01-01T00:00:00 TAI to match the intended and documented behaviour. This essentially changes the resulting times by 8.000082 seconds, the initial offset between TAI and UTC. [#11249]

Version 4.2 (2020-11-24)

New Features

astropy.convolution

• Methods convolve and convolve_fft both now return Quantity arrays if user input is given in one. [#10822]

astropy.coordinates

• Numpy functions that broadcast, change shape, or index (like np.broadcast_to, np.rot90, or np.roll) now work on coordinates, frames, and representations. [#10337]

• Add a new science state astropy.coordinates.erfa_astrom.erfa_astrom and two classes ErfaAstrom, ErfaAstromInterpolator as wrappers to the pyerfa astrometric functions used in the coordinate transforms. Using ErfaAstromInterpolator, which interpolates astrometric properties for SkyCoord instances with arrays of obstime, can dramatically speed up coordinate transformations while keeping microarcsecond resolution. Depending on needed precision and the obstime array in question, speed ups reach factors of 10x to >100x. [#10647]

• galactocentric_frame_defaults can now also be used as a registry, with user-defined parameter values and metadata. [#10624]

• Method .realize_frame from coordinate frames now accepts **kwargs, including representation_type. [#10727]

• Avoid an unnecessary call to erfa.epv00 in transformations between CIRS and ICRS, improving performance by 50 %. [#10814]

• A new equatorial coordinate frame, with RA and Dec measured w.r.t to the True Equator and Equinox (TETE). This frame is commonly known as “apparent place” and is the correct frame for coordinates returned from JPL Horizons. [#10867]

• Added a context manager impose_finite_difference_dt to the TransformGraph class to override the finite-difference time step attribute (finite_difference_dt) for all transformations in the graph with that attribute. [#10341]

• Improve performance of SpectralCoord by refactoring internal implementation. [#10398]

astropy.cosmology

• The final version of the Planck 2018 cosmological parameters are included as the Planck18 object, which is now the default cosmology. The parameters are identical to those of the Planck18_arXiv_v2 object, which is now deprecated and will be removed in a future release. [#10915]

astropy.modeling

• Added NFW profile and tests to modeling package [#10505]

• Added missing logic for evaluate to compound models [#10002]

• Stop iteration in FittingWithOutlierRemoval before reaching niter if the masked points are no longer changing. [#10642]

• Keep a (shallow) copy of fit_info from the last iteration of the wrapped fitter in FittingWithOutlierRemoval and also record the actual number of iterations performed in it. [#10642]

• Added attributes for fitting uncertainties (covariance matrix, standard deviations) to models. Parameter covariance matrix can be accessed via model.cov_matrix, standard deviations by model.stds or individually for each parameter by parameter.std. Currently implemented for LinearLSQFitter and LevMarLSQFitter. [#10552]

• N-dimensional least-squares statistic and specific 1,2,3-D methods [#10670]

astropy.stats

• Added circstd function to obtain a circular standard deviation. [#10690]

astropy.table

• Allow initializing a Table using a list of names in conjunction with a dtype from a numpy structured array. The list of names overrides the names specified in the dtype. [#10419]

astropy.time

• Add new isclose() method to Time and TimeDelta classes to allow comparison of time objects to within a specified tolerance. [#10646]

• Improve initialization time by a factor of four when creating a scalar Time object in a format like unix or cxcsec (time delta from a reference epoch time). [#10406]

• Improve initialization time by a factor of ~25 or more for large arrays of string times in ISO, ISOT or year day-of-year formats. This is done with a new C-based time parser that can be adapted for other fixed-format custom time formats. [#10360]

• Numpy functions that broadcast, change shape, or index (like np.broadcast_to, np.rot90, or np.roll) now work on times. [#10337, #10502]

astropy.timeseries

• Improve memory and speed performance when iterating over the entire time column of a TimeSeries object. Previously this involved O(N^2) operations and memory. [#10889]

astropy.units

• Quantity.to has gained a copy option to allow copies to be avoided when the units do not change. [#10517]

• Added the spat unit of solid angle that represents the full sphere. [#10726]

astropy.utils

• ShapedLikeNDArray has gained the capability to use numpy functions that broadcast, change shape, or index. [#10337]

• get_free_space_in_dir now takes a new unit keyword and check_free_space_in_dir takes size defined as Quantity. [#10627]

• New astropy.utils.data.conf.allow_internet configuration item to control downloading data from the Internet. Setting allow_internet=False is the same as remote_timeout=0. Using remote_timeout=0 to control internet access will stop working in a future release. [#10632]

• New is_url function so downstream packages do not have to secretly use the hidden _is_url anymore. [#10684]

astropy.visualization

• Added the Quadrangle patch for WCSAxes for a latitude-longitude quadrangle. Unlike matplotlib.patches.Rectangle, the edges of this patch will be rendered as curved lines if appropriate for the WCS transformation. [#10862]

• The position of tick labels are now only calculated when needed. If any text parameters are changed (color, font weight, size etc.) that don’t effect the tick label position, the positions are not recomputed, improving performance. [#10806]

astropy.wcs

• WCS.to_header() now appends comments to SIP coefficients. [#10480]

• A new property dropped_world_dimensions has been added to SlicedLowLevelWCS to record information about any world axes removed by slicing a WCS. [#10195]

• New WCS.proj_plane_pixel_scales() and WCS.proj_plane_pixel_area() methods to return pixel scales and area, respectively, as Quantity. [#10872]

API Changes

astropy.config

• set_temp_config now preserves the existing cache rather than deleting it and relying on reloading it from the previous config file. This ensures that any programmatically made changes are preserved as well. [#10474]

• Configuration path detection logic has changed: Now, it looks for ~ first before falling back to older logic. In addition, HOMESHARE is no longer used in Windows. [#10705]

astropy.coordinates

• The passing of frame classes (as opposed to frame instances) to the transform_to() methods of low-level coordinate-frame classes has been deprecated. Frame classes can still be passed to the transform_to() method of the high-level SkyCoord class, and using SkyCoord is recommended for all typical use cases of transforming coordinates. [#10475]

astropy.stats

• Added a grow parameter to SigmaClip, sigma_clip and sigma_clipped_stats, to allow expanding the masking of each deviant value to its neighbours within a specified radius. [#10613]

• Passing float n to poisson_conf_interval when using interval='kraft-burrows-nousek' now raises TypeError as its value must be an integer. [#10838]

astropy.table

• Change Table.columns.keys() and Table.columns.values() to both return generators instead of a list. This matches the behavior for Python dict objects. [#10543]

• Removed the FastBST and FastRBT indexing engines because they depend on the bintrees package, which is no longer maintained and is deprecated. Instead, use the SCEngine indexing engine, which is similar in performance and relies on the sortedcontainers package. [#10622]

• When slicing a mixin column in a table that had indices, the indices are no longer copied since they generally are not useful, having the wrong shape. With this, the behaviour becomes the same as that for a regular Column. (Note that this does not affect slicing of a table; sliced columns in those will continue to carry a sliced version of any indices). [#10890]

• Change behavior so that when getting a single item out of a mixin column such as Time, TimeDelta, SkyCoord or Quantity, the info attribute is no longer copied. This improves performance, especially when the object is an indexed column in a Table. [#10889]

• Raise a TypeError when a scalar column is added to an unsized table. [#10476]

• The order of columns when creating a table from a list of dict may be changed. Previously, the order was alphabetical because the dict keys were assumed to be in random order. Since Python 3.7, the keys are always in order of insertion, so Table now uses the order of keys in the first row to set the column order. To alphabetize the columns to match the previous behavior, use t = t[sorted(t.colnames)]. [#10900]

astropy.time

• Refactor Time and TimeDelta classes to inherit from a common TimeBase class. The TimeDelta class no longer inherits from Time. A number of methods that only apply to Time (e.g. light_travel_time) are no longer available in the TimeDelta class. [#10656]

astropy.units

• The bar unit is no longer wrongly considered an SI unit, meaning that SI decompositions like (u.kg*u.s**-2* u.sr**-1 * u.nm**-1).si will no longer include it. [#10586]

astropy.utils

• Shape-related items from astropy.utils.misc – ShapedLikeNDArray, check_broadcast, unbroadcast, and IncompatibleShapeError – have been moved to their own module, astropy.utils.shapes. They remain importable from astropy.utils. [#10337]

• check_hashes keyword in check_download_cache is deprecated and will be removed in a future release. [#10628]

• hexdigest keyword in import_file_to_cache is deprecated and will be removed in a future release. [#10628]

Bug Fixes

astropy.config

• Fix a few issues with generate_config when used with other packages. [#10893]

astropy.coordinates

• Fixed a bug in the coordinate-frame attribute CoordinateAttribute where the internal transformation could behave differently depending on whether the input was a low-level coordinate frame or a high-level SkyCoord. CoordinateAttribute now always performs a SkyCoord-style internal transformation, including the by-default merging of frame attributes. [#10475]

astropy.modeling

• Fixed an issue of Model.render when the input out datatype is not float64. [#10542]

astropy.visualization

• Fix support for referencing WCSAxes coordinates by their world axes names. [#10484]

astropy.wcs

• Objective functions called by astropy.wcs.fit_wcs_from_points were treating longitude and latitude distances equally. Now longitude scaled properly. [#10759]

Other Changes and Additions

• Minimum version of required Python is now 3.7. [#10900]

• Minimum version of required Numpy is now 1.17. [#10664]

• Minimum version of required Scipy is now 1.1. [#10900]

• Minimum version of required PyYAML is now 3.13. [#10900]

• Minimum version of required Matplotlib is now 3.0. [#10900]

• The private _erfa module has been converted to its own package, pyerfa, which is a required dependency for astropy, and can be imported with import erfa. Importing _erfa from astropy will give a deprecation warning. [#10329]

• Added optimize=True flag to calls of yacc.yacc (as already done for lex.lex) to allow running in python -OO session without raising an exception in astropy.units.format. [#10379]

• Shortened FITS comment strings for some D2IM and CPDIS FITS keywords to reduce the number of FITS VerifyWarning warnings when working with WCSes containing lookup table distortions. [#10513]

• When importing astropy without first building the extension modules first, raise an error directly instead of trying to auto-build. [#10883]

Version 4.1 (2020-10-21)

New Features

astropy.config

• Add new function generate_config to generate the configuration file and include it in the documentation. [#10148]

• ConfigNamespace.__iter__ and ConfigNamespace.keys now yield ConfigItem names defined within it. Similarly, items and values would yield like a Python dictionary would. [#10139]

astropy.coordinates

• Added a new SpectralCoord class that can be used to define spectral coordinates and transform them between different velocity frames. [#10185]

• Angle parsing now supports cardinal direction in the cases where angles are initialized as string instances. eg "17°53'27"W".[#9859]

• Allow in-place modification of array-valued Frame and SkyCoord objects. This provides limited support for updating coordinate data values from another coordinate object of the same class and equivalent frame attributes. [#9857]

• Added a robust equality operator for comparing SkyCoord, frame, and representation objects. A comparison like sc1 == sc2 will now return a boolean or boolean array where the objects are strictly equal in all relevant frame attributes and coordinate representation values. [#10154]

• Added the True Equator Mean Equinox (TEME) frame. [#10149]

• The Galactocentric frame will now use the “latest” parameter definitions by default. This currently corresponds to the values defined in v4.0, but will change with future releases. [#10238]

• The SkyCoord.from_name() and Sesame name resolving functionality now is able to cache results locally and will do so by default. [#9162]

• Allow in-place modification of array-valued Representation and Differential objects, including of representations with attached differentials. [#10210]

astropy.io.ascii

• Functional Units can now be processed in CDS-tables. [#9971]

• Allow reading in ASCII tables which have duplicate column names. [#9939]

• Fixed failure of ASCII fast_reader to handle names, include_names, exclude_names arguments for RDB formatted tables. Homogenised checks and exceptions for invalid names arguments. Improved performance when parsing “wide” tables with many columns. [#10306]

• Added type validation of key arguments in calls to io.ascii.read() and io.ascii.write() functions. [#10005]

astropy.io.misc

• Added serialization of parameter constraints fixed and bounds. [#10082]

• Added ‘functional_models.py’ and ‘physical_models.py’ to asdf/tags/transform, with to allow serialization of all functional and physical models. [#10028, #10293]

• Fix ASDF serialization of circular model inverses, and remove explicit calls to asdf.yamlutil functions that became unnecessary in asdf 2.6.0. [#10189, #10384]

astropy.io.fits

• Added support for writing Dask arrays to disk efficiently for ImageHDU and PrimaryHDU. [#9742]

• Add HDU name and ver to FITSDiff report where appropriate [#10197]

astropy.io.votable

• New exceptions.conf.max_warnings configuration item to control the number of times a type of warning appears before being suppressed. [#10152]

• No longer ignore attributes whose values were specified as empty strings. [#10583]

astropy.modeling

• Added Plummer1D model to functional_models. [#9896]

• Added UnitsMapping model and Model.coerce_units to support units on otherwise unitless models. [#9936]

• Added domain and window attributes to repr and str. Fixed bug with _format_repr in core.py. [#9941]

• Polynomial attributes domain and window are now tuples of size 2 and are validated. repr and print show only their non-default values. [#10145]

• Added replace_submodel() method to CompoundModel to modify an existing instance. [#10176]

• Delay construction of CompoundModel inverse until property is accessed, to support ASDF deserialization of circular inverses in component models. [#10384]

astropy.nddata

• Added support in the bitmask module for using mnemonic bit flag names when specifying the bit flags to be used or ignored when converting a bit field to a boolean. [#10095, #10208]

• Added reshape_as_blocks function to reshape a data array into blocks, which is useful to efficiently apply functions on block subsets of the data instead of using loops. The reshaped array is a view of the input data array. [#10214]

• Added a cache keyword option to allow caching for CCDData.read if filename is a URL. [#10265]

astropy.table

• Added ability to specify a custom matching function for table joins. In particular this makes it possible to do cross-match table joins on SkyCoord, Quantity, or standard columns, where column entries within a specified distance are considered to be matched. [#10169]

• Added units and descriptions keyword arguments to the Table object initialization and Table.read() methods. This allows directly setting the unit and description for the table columns at the time of creating or reading the table. [#9671]

• Make table Row work as mappings, by adding .keys() and .values() methods. With this **row becomes possible, as does, more simply, turning a Row into a dictionary with dict(row). [#9712]

• Added two new Table methods .items() and .values(), which return respectively tbl.columns.items() (iterator over name, column tuples) and tbl.columns.values() (list of columns) for a Table object tbl. [#9780]

• Added new Table method .round(), which rounds numeric columns to the specified number of decimals. [#9862]

• Updated to_pandas() and from_pandas() to use and support Pandas nullable integer data type for masked integer data. [#9541]

• The HDF5 writer, write_table_hdf5(), now allows passing through additional keyword arguments to the h5py.Group.create_dataset(). [#9602]

• Added capability to add custom table attributes to a Table subclass. These attributes are persistent and can be set during table creation. [#10097]

• Added support for SkyCoord mixin columns in dstack, vstack and insert_row functions. [#9857]

• Added support for coordinate Representation and Differential mixin columns. [#10210]

astropy.time

• Added a new time format unix_tai which is essentially Unix time but with leap seconds included. More precisely, this is the number of seconds since 1970-01-01 00:00:08 TAI and corresponds to the CLOCK_TAI clock available on some linux platforms. [#10081]

astropy.units

• Added torr pressure unit. [#9787]

• Added the equal_nan keyword argument to isclose and allclose, and updated the docstrings. [#9849]

• Added Rankine temperature unit. [#9916]

• Added integrated flux unit conversion to spectral_density equivalency. [#10015]

• Changed pixel_scale equivalency to allow scales defined in any unit. [#10123]

• The quantity_input decorator now optionally allows passing through numeric values or numpy arrays with numeric dtypes to arguments where dimensionless_unscaled is an allowed unit. [#10232]

astropy.utils

• Added a new MetaAttribute class to support easily adding custom attributes to a subclass of classes like Table or NDData that have a meta attribute. [#10097]

astropy.visualization

• Added invalid keyword to SqrtStretch, LogStretch, PowerStretch, and ImageNormalize classes and the simple_norm function. This keyword is used to replace generated NaN values. [#10182]

• Fixed an issue where ticks were sometimes not drawn at the edges of a spherical projection on a WCSAxes. [#10442]

astropy.wcs

• WCS objects with a spectral axis will now return SpectralCoord objects when calling pixel_to_world instead of Quantity, and can now take either Quantity or SpectralCoord as input to pixel_to_world. [#10185]

• Implemented support for the -TAB algorithm (WCS Paper III). [#9641]

• Added an _as_mpl_axes method to the HightLevelWCSWrapper class. [#10138]

• Add .upper() to ctype or ctype names to wcsapi/fitwcs.py to mitigate bugs from unintended lower/upper case issues [#10557]

API Changes

astropy.coordinates

• The equality operator for comparing SkyCoord, frame, and representation objects was changed. A comparison like sc1 == sc2 was previously equivalent to sc1 is sc2. It will now return a boolean or boolean array where the objects are strictly equal in all relevant frame attributes and coordinate representation values. If the objects have different frame attributes or representation types then an exception will be raised. [#10154]

• `SkyCoord.radial_velocity_correction` now allows you to pass an `obstime` directly when the `SkyCoord` also has an `obstime` set. In this situation, the position of the `SkyCoord` has space motion applied to correct to the passed `obstime`. This allows mm/s radial velocity precision for objects with large space motion. [#10094]

• For consistency with other astropy classes, coordinate Representations and Differentials can now be initialized with an instance of their own class if that instance is passed in as the first argument. [#10210]

astropy.io.ascii

• Changed the behavior when reading a table where both the names argument is provided (to specify the output column names) and the converters argument is provided (to specify column conversion functions). Previously the converters dict names referred to the input table column names, but now they refer to the output table column names. [#9739]

astropy.io.votable

• For FIELDs with datatype=”char”, store the values as strings instead of bytes. [#9505]

astropy.table

• Table.from_pandas now supports a units dictionary as argument to pass units for columns in the DataFrame. [#9472]

astropy.time

• Require that in_subfmt and out_subfmt properties of a Time object have allowed values at the time of being set, either when creating the object or when setting those properties on an existing Time instance. Previously the validation of those properties was not strictly enforced. [#9868]

astropy.utils

• Changed the exception raised by get_readable_fileobj on missing compression modules (for bz2 or lzma/xz support) to ModuleNotFoundError, consistent with io.fits file handlers. [#9761]

astropy.visualization

• Deprecated the imshow_only_kwargs keyword in imshow_norm. [#9915]

• Non-finite input values are now automatically excluded in HistEqStretch and InvertedHistEqStretch. [#10177]

• The PowerDistStretch and InvertedPowerDistStretch a value is restricted to be a >= 0 in addition to a != 1. [#10177]

• The PowerStretch, LogStretch, and InvertedLogStretch a value is restricted to be a > 0. [#10177]

• The AsinhStretch and SinhStretch a value is restricted to be 0 < a <= 1. [#10177]

Bug Fixes

astropy.coordinates

• Fix a bug where for light deflection by the Sun it was always assumed that the source was at infinite distance, which in the (rare and) absolute worst-case scenario could lead to errors up to 3 arcsec. [#10666]

astropy.io.votable

• For FIELDs with datatype=”char”, store the values as strings instead of bytes. [#9505]

astropy.table

• Fix a bug that prevented Time columns from being used to sort a table. [#10824]

astropy.wcs

• WCS objects with a spectral axis will now return SpectralCoord objects when calling pixel_to_world instead of Quantity (note that SpectralCoord is a sub-class of Quantity). [#10185]

• Add .upper() to ctype or ctype names to wcsapi/fitwcs.py to mitigate bugs from unintended lower/upper case issues [#10557]

• Added bounds to fit_wcs_from_points to ensure CRPIX is on input image. [#10346]

Other Changes and Additions

• The way in which users can specify whether to build astropy against existing installations of C libraries rather than the bundled one has changed, and should now be done via environment variables rather than setup.py flags (e.g. –use-system-erfa). The available variables are ASTROPY_USE_SYSTEM_CFITSIO, ASTROPY_USE_SYSTEM_ERFA, ASTROPY_USE_SYSTEM_EXPAT, ASTROPY_USE_SYSTEM_WCSLIB, and ASTROPY_USE_SYSTEM_ALL. These should be set to 1 to build against the system libraries. [#9730]

• The infrastructure of the package has been updated in line with the APE 17 roadmap (astropy/astropy-APEs). The main changes are that the python setup.py test and python setup.py build_docs commands will no longer work. The easiest way to replicate these commands is to install the tox (https://tox.readthedocs.io) package and run tox -e test and tox -e build_docs. It is also possible to run pytest and sphinx directly. Other significant changes include switching to setuptools_scm to manage the version number, and adding a pyproject.toml to opt in to isolated builds as described in PEP 517/518. [#9726]

• Bundled expat is updated to version 2.2.9. [#10038]

• Increase minimum asdf version to 2.6.0. [#10189]

• The bundled version of PLY was updated to 3.11. [#10258]

• Removed dependency on scikit-image. [#10214]

Version 4.0.5 (2021-03-26)

Bug Fixes

astropy.io.fits

• Fix bug where manual fixes to invalid header cards were not preserved when saving a FITS file. [#11108]

• Fix parsing of RVKC header card patterns that were not recognised where multiple spaces were separating field-specifier and value like “DP1.AXIS.1: 1”. [#11301]

• Fix misleading missing END card error when extra data are found at the end of the file. [#11285]

• Fix incorrect wrapping of long card values as CONTINUE cards when some words in the value are longer than a single card. [#11304]

astropy.io.misc

• Fixed problem when writing serialized metadata to HDF5 using h5py >= 3.0. With the newer h5py this was writing the metadata table as a variable-length string array instead of the previous fixed-length bytes array. Fixed astropy to force using a fixed-length bytes array. [#11359]

astropy.modeling

• Change Voigt1D function to use Humlicek’s approximation to avoid serious inaccuracies + option to use (compiled) scipy.special.wofz error function for yet more accurate results. [#11177]

astropy.table

• Fixed bug when initializing a Table with a column as list of Quantity, for example Table({'x': [1*u.m, 2*u.m]}). Previously this resulted in an object dtype with no column unit set, but now gives a float array with the correct unit. [#11329]

• Fixed byteorder conversion in to_pandas(), which had incorrectly triggered swapping when native endianness was stored with explicit dtype code '<' (or '>') instead of '='. [#11288, #11294]

• Fixed a compatibility issue with numpy 1.21. Initializing a Table with a column like ['str', np.ma.masked] was failing in tests due to a change in numpy. [#11364]

• Fixed bug when validating the inputs to table.hstack, table.vstack, and table.dstack. Previously, mistakenly calling table.hstack(t1, t2) (instead of table.hstack([t1, t2])) would return t1 instead of raising an exception. [#11336]

• Fixed byteorder conversion in to_pandas(), which had incorrectly triggered swapping when native endianness was stored with explicit dtype code '<' (or '>') instead of '='. [#11288]

astropy.time

• Fix leap second update when using a non english locale. [#11062]

• Fix default assumed location to be the geocenter when transforming times to and from solar-system barycenter scales. [#11134]

• Fix inability to write masked times with formatted_value. [#11195]

astropy.units

• Ensure keepdims works for taking mean, std, and var of Quantity. [#11198]

• For Quantity.to_string(), ensure that the precision argument is also used when the format is not latex. [#11145]

astropy.wcs

• Allow “un-setting” of auxiliary WCS parameters in the aux attribute of Wcsprm. [#11166]

Version 4.0.4 (2020-11-24)

Bug Fixes

astropy.coordinates

• The norm() method for RadialDifferential no longer requires base to be specified. The norm() method for other non-Cartesian differential classes now gives a clearer error message if base is not specified. [#10969]

• The transformations between ICRS and any of the heliocentric ecliptic frames (HeliocentricMeanEcliptic, HeliocentricTrueEcliptic, and HeliocentricEclipticIAU76) now correctly account for the small motion of the Sun when transforming a coordinate with velocity information. [#10970]

astropy.io.ascii

• Partially fixed a performance issue when reading in parallel mode. Parallel reading currently has substantially worse performance than the default serial reading, so we now ignore the parallel option and fall back to serial reading. [#10880]

• Fixed a bug where “” (blank string) as input data for a boolean type column was causing an exception instead of indicating a masked value. As a consequence of the fix, the values “0” and “1” are now also allowed as valid inputs for boolean type columns. These new allowed values apply for both ECSV and for basic character-delimited data files (‘basic’ format with appropriate converters specified). [#10995]

astropy.modeling

• Fixed use of weights with LinearLSQFitter. [#10687]

astropy.stats

• Fixed an issue in biweight stats when MAD=0 to give the same output with and without an input axis. [#10912]

astropy.time

• Fix a problem with the plot_date format for matplotlib >= 3.3 caused by a change in the matplotlib plot date default reference epoch in that release. [#10876]

• Improve initialization time by a factor of four when creating a scalar Time object in a format like unix or cxcsec (time delta from a reference epoch time). [#10406]

astropy.visualization

• Fixed the calculation of the tight bounding box of a WCSAxes. This should also significantly improve the application of tight_layout() to figures containing WCSAxes. [#10797]

Version 4.0.3 (2020-10-14)

Bug Fixes

astropy.table

• Fixed a small bug where initializing an empty Column with a structured dtype with a length and a shape failed to give the requested dtype. [#10819]

Other Changes and Additions

• Fixed installation of the source distribution with pip<19. [#10837, #10852]

Version 4.0.2 (2020-10-10)

New Features

astropy.utils

• astropy.utils.data.download_file now supports FTPS/FTP over TLS. [#9964]

• astropy.utils.data now uses a lock-free mechanism for caching. This new mechanism uses a new cache layout and so ignores caches created using earlier mechanisms (which were causing lockups on clusters). The two cache formats can coexist but do not share any files. [#10437, #10683]

• astropy.utils.data now ignores the config item astropy.utils.data.conf.download_cache_lock_attempts since no locking is done. [#10437, #10683]

• astropy.utils.data.download_file and related functions now interpret the parameter or config file setting timeout=0 to mean they should make no attempt to download files. [#10437, #10683]

• astropy.utils.import_file_to_cache now accepts a keyword-only argument replace, defaulting to True, to determine whether it should replace existing files in the cache, in a way as close to atomic as possible. [#10437, #10683]

• astropy.utils.data.download_file and related functions now treat http://example.com and http://example.com/ as equivalent. [#10631]

astropy.wcs

• The new auxiliary WCS parameters added in WCSLIB 7.1 are now exposed as the aux attribute of Wcsprm. [#10333]

• Updated bundled version of WCSLIB to v7.3. [#10433]

Bug fixes

astropy.config

• Added an extra fallback to os.expanduser('~') when trying to find the user home directory. [#10570]

astropy.constants

• Corrected definition of parsec to 648 000 / pi AU following IAU 2015 B2 [#10569]

astropy.convolution

• Fixed a bug where a float-typed integers in the argument x_range of astropy.convolution.utils.discretize_oversample_1D (and the 2D version as well) fails because it uses numpy.linspace, which requires an int. [#10696]

astropy.coordinates

• Ensure that for size-1 array SkyCoord and coordinate frames the attributes also properly become scalars when indexed with 0. [#10113]

• Fixed a bug where SkyCoord.separation() and SkyCoord.separation_3d were not accepting a frame object. [#10332]

• Ensure that the lon values in SkyOffsetFrame are wrapped correctly at 180 degree regardless of how the underlying data is represented. [#10163]

• Fixed an error in the obliquity of the ecliptic when transforming to/from the *TrueEcliptic coordinate frames. The error would primarily result in an inaccuracy in the ecliptic latitude on the order of arcseconds. [#10129]

• Fixed an error in the computation of the location of solar system bodies where the Earth location of the observer was ignored during the correction for light travel time. [#10292]

• Ensure that coordinates with proper motion that are transformed to other coordinate frames still can be represented properly. [#10276]

• Improve the error message given when trying to get a cartesian representation for coordinates that have both proper motion and radial velocity, but no distance. [#10276]

• Fixed an error where SkyCoord.apply_space_motion would return incorrect results when no distance is set and proper motion is high. [#10296]

• Make the parsing of angles thread-safe so that Angle can be used in Python multithreading. [#10556]

• Fixed reporting of EarthLocation.info which previously raised an exception. [#10592]

astropy.io.ascii

• Fixed a bug with the C fast_reader not correctly parsing newlines when delimiter was also set to \n or \r; ensured consistent handling of input strings without newline characters. [#9929]

astropy.io.fits

• Fix integer formats of TFORMn=Iw columns in ASCII tables to correctly read values exceeding int32 - setting int16, int32 or int64 according to w. [#9901]

• Fix unclosed memory-mapped FITS files in FITSDiff when difference found. [#10159]

• Fix crash when reading an invalid table file. [#10171]

• Fix duplication issue when setting a keyword ending with space. [#10482]

• Fix ResourceWarning with fits.writeto and pathlib.Path object. [#10599]

• Fix repr for commentary cards and strip spaces for commentary keywords. [#10640]

• Fix compilation of cfitsio with Xcode 12. [#10772]

• Fix handling of 1-dimensional arrays with a single element in BinTableHDU [#10768]

astropy.io.misc

• Fix id URL in baseframe-1.0.0 ASDF schema. [#10223]

• Write keys to ASDF only if the value is present, to account for a change in behavior in asdf 2.8. [#10674]

astropy.io.registry

• Fix Table.(read|write).help when reader or writer has no docstring. [#10460]

astropy.io.votable

• Fixed parsing failure of VOTable with no fields. When detecting a non-empty table with no fields, the following warning/exception is issued: E25 “No FIELDs are defined; DATA section will be ignored.” [#10192]

astropy.modeling

• Fixed a problem with mapping input_units and return_units of a CompoundModel to the units of the constituent models. [#10158]

• Removed hard-coded names of inputs and outputs. [#10174]

• Fixed a problem where slicing a CompoundModel by name will crash if there fix_inputs operators are present. [#10224]

• Removed a limitation of fitting of data with units with compound models without units when the expression involves operators other than addition and subtraction. [#10415]

• Fixed a problem with fitting Linear1D and Planar2D in model sets. [#10623]

• Fixed reported module name of math_functions model classes. [#10694]

• Fixed reported module name of tabular model classes. [#10709]

• Do not create new math_functions models for ufuncs that are only aliases (divide and mod). [#10697]

• Fix calculation of the Moffat2D derivative with respect to gamma. [#10784]

astropy.stats

• Fixed an API regression where SigmaClip.__call__ would convert masked elements to nan and upcast the dtype to float64 in its output MaskedArray when using the axis parameter along with the defaults masked=True and copy=True. [#10610]

• Fixed an issue where fully masked MaskedArray input to sigma_clipped_stats gave incorrect results. [#10099]

• Fixed an issue where sigma_clip and SigmaClip.__call__ would return a masked array instead of a ndarray when masked=False and the input was a full-masked MaskedArray. [#10099]

• Fixed bug with funcs.poisson_conf_interval where an integer for N with interval='kraft-burrows-nousek' would throw an error with mpmath backend. [#10427]

• Fixed bug in funcs.poisson_conf_interval with interval='kraft-burrows-nousek' where certain combinations of source and background count numbers led to ValueError due to the choice of starting value for numerical optimization. [#10618]

astropy.table

• Fixed a bug when writing a table with mixin columns to FITS, ECSV or HDF5. If one of the data attributes of the mixin (e.g. skycoord.ra) had the same name as one of the table column names (ra), the column (ra) would be dropped when reading the table back. [#10222]

• Fixed a bug when sorting an indexed table on the indexed column after first sorting on another column. [#10103]

• Fixed a bug in table argsort when called with reverse=True for an indexed table. [#10103]

• Fixed a performance regression introduced in #9048 when initializing a table from Python lists. Also fixed incorrect behavior (for data types other than float) when those lists contain np.ma.masked elements to indicate masked data. [#10636]

• Avoid modifying .meta when serializing columns to FITS. [#10485]

• Avoid crash when reading a FITS table that contains mixin info and PyYAML is missing. [#10485]

astropy.time

• Ensure that for size-1 array Time, the location also properly becomes a scalar when indexed with 0. [#10113]

astropy.units

• Refined test_parallax to resolve difference between 2012 and 2015 definitions. [#10569]

astropy.utils

• The default IERS server has been updated to use the FTPS server hosted by CDDIS. [#9964]

• Fixed memory allocation on 64-bit systems within xml.iterparse [#10076]

• Fix case where None could be used in a numerical computation. [#10126]

astropy.visualization

• Fixed a bug where the ImageNormalize clip keyword was ignored when used with calling the object on data. [#10098]

• Fixed a bug where axes.xlabel/axes.ylabel where not correctly set nor returned on an EllipticalFrame class WCSAxes plot. [#10446]

astropy.wcs

• Handled WCS 360 -> 0 deg crossover in fit_wcs_from_points [#10155]

• Do not issue DATREF warning when MJDREF has default value. [#10440]

• Fixed a bug due to which naxis argument was ignored if header was supplied during the initialization of a WCS object. [#10532]

Other Changes and Additions

• Improved the speed of sorting a large Table on a single column by a factor of around 5. [#10103]

• Ensure that astropy can be used inside Application bundles built with pyinstaller. [#8795]

• Updated the bundled CFITSIO library to 3.49. See cextern/cfitsio/docs/changes.txt for additional information. [#10256, #10665]

• extract_array raises a ValueError if the data type of the input array is inconsistent with the fill_value. [#10602]

Version 4.0.1 (2020-03-27)

Bug fixes

astropy.config

• Fixed a bug where importing a development version of a package that uses astropy configuration system can result in a ~/.astropy/config/package..cfg file. [#9975]

astropy.coordinates

• Fixed a bug where a vestigal trace of a frame class could persist in the transformation graph even after the removal of all transformations involving that frame class. [#9815]

• Fixed a bug with TransformGraph.remove_transform() when the “from” and “to” frame classes are not explicitly specified. [#9815]

• Read-only longitudes can now be passed in to EarthLocation even if they include angles outside of the range of -180 to 180 degrees. [#9900]

• `SkyCoord.radial_velocity_correction` no longer raises an Exception when space motion information is present on the SkyCoord. [#9980]

astropy.io

• Fixed a bug that prevented the unified I/O infrastructure from working with datasets that are represented by directories rather than files. [#9866]

astropy.io.ascii

• Fixed a bug in the fast_reader C parsers incorrectly returning entries of isolated positive/negative signs as float instead of str. [#9918]

• Fixed a segmentation fault in the fast_reader C parsers when parsing an invalid file with guess=True and the file contains inconsistent column numbers in combination with a quoted field; e.g., "1  2\n 3  4 '5'". [#9923]

• Magnitude, decibel, and dex can now be stored in ecsv files. [#9933]

astropy.io.misc

• Magnitude, decibel, and dex can now be stored in hdf5 files. [#9933]

• Fixed serialization of polynomial models to include non default values of domain and window values. [#9956, #9961]

• Fixed a bug which affected overwriting tables within hdf5 files. Overwriting an existing path with associated column meta data now also overwrites the meta data associated with the table. [#9950]

• Fixed serialization of Time objects with location under time-1.0.0 ASDF schema. [#9983]

astropy.io.fits

• Fix regression with GroupsHDU which needs to modify the header to handle invalid headers, and fix accessing .data for empty HDU. [#9711, #9934]

• Fix fitsdiff when its arguments are directories that contain other directories. [#9711]

• Fix writing noncontiguous data to a compressed HDU. [#9958]

• Added verification of disp (TDISP) keyword to fits.Column and extended tests for TFORM and TDISP validation. [#9978]

• Fix checksum verification to process all HDUs instead of only the first one because of the lazy loading feature. [#10012]

• Allow passing output_verify to .close when using the context manager. [#10030]

• Prevent instantiation of PrimaryHDU and ImageHDU with a scalar. [#10041]

• Fix column access by attribute with FITS_rec: columns with scaling or columns from ASCII tables where not properly converted when accessed by attribute name. [#10069]

astropy.io.misc

• Magnitude, decibel, and dex can now be stored in hdf5 files. [#9933]

• Fixed serialization of polynomial models to include non default values of domain and window values. [#9956, #9961]

• Fixed a bug which affected overwriting tables within hdf5 files. Overwriting an existing path with associated column meta data now also overwrites the meta data associated with the table. [#9950]

• Fixed serialization of Time objects with location under time-1.0.0 ASDF schema. [#9983]

astropy.modeling

• Fixed a bug in setting default values of parameters of orthonormal polynomials when constructing a model set. [#9987]

astropy.table

• Fixed bug in Table.reverse for tables that contain non-mutable mixin columns (like SkyCoord) for which in-place item update is not allowed. [#9839]

• Tables containing Magnitude, decibel, and dex columns can now be saved to ecsv files. [#9933]

• Fixed bug where adding or inserting a row fails on a table with an index defined on a column that is not the first one. [#10027]

• Ensured that table.show_in_browser also worked for mixin columns like Time and SkyCoord. [#10068]

astropy.time

• Fix inaccuracy when converting between TimeDelta and datetime.timedelta. [#9679]

• Fixed exception when changing format in the case when out_subfmt is defined and is incompatible with the new format. [#9812]

• Fixed exceptions in Time.to_value(): when supplying any subfmt argument for string-based formats like ‘iso’, and for subfmt='long' for the formats ‘byear’, ‘jyear’, and ‘decimalyear’. [#9812]

• Fixed bug where the location attribute was lost when creating a new Time object from an existing Time or list of Time objects. [#9969]

• Fixed a bug where an exception occurred when creating a Time object if the val1 argument was a regular double and the val2 argument was a longdouble. [#10034]

astropy.timeseries

• Fixed issue with reference time for the transit_time parameter returned by the BoxLeastSquares periodogram. Now, the transit_time will be within the range of the input data and arbitrary time offsets/zero points no longer affect results. [#10013]

astropy.units

• Fix for quantity_input annotation raising an exception on iterable types that don’t define a general __contains__ for checking if None is contained (e.g. Enum as of python3.8), by instead checking for instance of Sequence. [#9948]

• Fix for u.Quantity not taking into account ndmin if constructed from another u.Quantity instance with different but convertible unit [#10066]

astropy.utils

• Fixed deprecated_renamed_argument not passing in user value to deprecated keyword when the keyword has no new name. [#9981]

• Fixed deprecated_renamed_argument not issuing a deprecation warning when deprecated keyword without new name is passed in as positional argument. [#9985]

• Fixed detection of read-only filesystems in the caching code. [#10007]

astropy.visualization

• Fixed bug from matplotlib >=3.1 where an empty Quantity array is sent for unit conversion as an empty list. [#9848]

• Fix bug in ZScaleInterval to return the array minimum and maximum when there are less then min_npixels in the input array. [#9913]

• Fix a bug in simplifying axis labels that affected non-rectangular frames. [#8004, #9991]

Other Changes and Additions

• Increase minimum asdf version to 2.5.2. [#9996, #9819]

• Updated bundled version of WCSLIB to v7.2. [#10021]

Version 4.0 (2019-12-16)

New Features

astropy.config

• The config and cache directories and the name of the config file are now customizable. This allows affiliated packages to put their configuration files in locations other than CONFIG_DIR/.astropy/. [#8237]

astropy.constants

• The version of constants can be specified via ScienceState in a way that constants and units will be consistent. [#8517]

• Default constants now use CODATA 2018 and IAU 2015 definitions. [#8761]

• Constants can be pickled and unpickled. [#9377]

astropy.convolution

• Fixed a bug [#9168] where having a kernel defined using unitless astropy quantity objects would result in a crash [#9300]

astropy.coordinates

• Changed coordinates.solar_system_ephemeris to also accept local files as input. The ephemeris can now be selected by either keyword (e.g. ‘jpl’, ‘de430’), URL or file path. [#8767]

• Added a cylindrical property to SkyCoord for shorthand access to a CylindricalRepresentation of the coordinate, as is already available for other common representations. [#8857]

• The default parameters for the Galactocentric frame are now controlled by a ScienceState subclass, galactocentric_frame_defaults. New parameter sets will be added to this object periodically to keep up with ever-improved measurements of the solar position and motion. [#9346]

• Coordinate frame classes can now have multiple aliases by assigning a list of aliases to the class variable name. Any of the aliases can be used for attribute-style access or as the target of tranform_to() calls. [#8834]

• Passing a NaN to Distance no longer raises a warning. [#9598]

astropy.cosmology

• The pre-publication Planck 2018 cosmological parameters are included as the Planck2018_arXiv_v2 object. Please note that the values are preliminary, and when the paper is accepted a final version will be included as Planck18. [#8111]

astropy.io.ascii

• Removed incorrect warnings on Overflow when reading in FloatType 0.0 with use_fast_converter; synchronised IntType Overflow warning messages. [#9082]

astropy.io.misc

• Eliminate deprecated compatibility mode when writing Table metadata to HDF5 format. [#8899]

• Add support for orthogonal polynomial models to ASDF. [#9107]

astropy.io.fits

• Changed the fitscheck and fitsdiff script to use the argparse module instead of optparse. [#9148]

• Allow writing of Table objects with Time columns that are also table indices to FITS files. [#8077]

astropy.io.votable

• Support VOTable version 1.4. The main addition is the new element, TIMESYS, which allows defining of metadata for temporal coordinates much like COOSYS defines metadata for celestial coordinates. [#9475]

astropy.logger

• Added a configuration option to specify the text encoding of the log file, with the default behavior being the platform-preferred encoding. [#9203]

astropy.modeling

• Major rework of modeling internals. See modeling documentation for details. . [#8769]

• Add Tabular1D.inverse. [#9083]

• Model.rename was changed to add the ability to rename Model.inputs and Model.outputs. [#9220]

• New function fix_inputs to generate new models from others by fixing specific inputs variable values to constants. [#9135]

• inputs and outputs are now model instance attributes, and n_inputs and n_outputs are class attributes. Backwards compatible default values of inputs and outputs are generated. Model.inputs and Model.outputs are now settable which allows renaming them on per user case. [#9298]

• Add a new model representing a sequence of rotations in 3D around an arbitrary number of axes. [#9369]

• Add many of the numpy ufunc functions as models. [#9401]

• Add BlackBody model. [#9282]

• Add Drude1D model. [#9452]

• Added analytical King model (KingProjectedAnalytic1D). [#9084]

• Added Exponential1D and Logarithmic1D models. [#9351]

astropy.nddata

• Add a way for technically invalid but unambiguous units in a fits header to be parsed by CCDData. [#9397]

• NDData now only accepts WCS objects which implement either the high, or low level APE 14 WCS API. All WCS objects are converted to a high level WCS object, so NDData.wcs now always returns a high level APE 14 object. Not all array slices are valid for wcs objects, so some slicing operations which used to work may now fail. [#9067]

astropy.stats

• The biweight_location, biweight_scale, and biweight_midvariance functions now allow for the axis keyword to be a tuple of integers. [#9309]

• Added an ignore_nan option to the biweight_location, biweight_scale, and biweight_midvariance functions. [#9457]

• A numpy MaskedArray can now be input to the biweight_location, biweight_scale, and biweight_midvariance functions. [#9466]

• Removed the warning related to p0 in the Bayesian blocks algorithm. The caveat related to p0 is described in the docstring for Events. [#9567]

astropy.table

• Improved the implementation of Table.replace_column() to provide a speed-up of 5 to 10 times for wide tables. The method can now accept any input which convertible to a column of the correct length, not just Column subclasses. [#8902]

• Improved the implementation of Table.add_column() to provide a speed-up of 2 to 10 (or more) when adding a column to tables, with increasing benefit as the number of columns increases. The method can now accept any input which is convertible to a column of the correct length, not just Column subclasses. [#8933]

• Changed the implementation of Table.add_columns() to use the new Table.add_column() method. In most cases the performance is similar or slightly faster to the previous implementation. [#8933]

• MaskedColumn.data will now return a plain MaskedArray rather than the previous (unintended) masked_BaseColumn. [#8855]

• Added depth-wise stacking dstack() in higher level table operation. It help will in stacking table column depth-wise. [#8939]

• Added a new table equality method values_equal() which allows comparison table values to another table, list, or value, and returns an element-by-element equality table. [#9068]

• Added new join_type='cartesian' option to the join operation. [#9288]

• Allow adding a table column as a list of mixin-type objects, for instance t['q'] = [1 * u.m, 2 * u.m]. [#9165]

• Allow table join() using any sortable key column (e.g. Time), not just ndarray subclasses. A column is considered sortable if there is a <column>.info.get_sortable_arrays() method that is implemented. [#9340]

• Added Table.iterrows() for making row-wise iteration faster. [#8969]

• Allow table to be initialized with a list of dict where the dict keys are not the same in every row. The table column names are the set of all keys found in the input data, and any missing key/value pairs are turned into missing data in the table. [#9425]

• Prevent unnecessary ERFA warnings when indexing by Time columns. [#9545]

• Added support for sorting tables which contain non-mutable mixin columns (like SkyCoord) for which in-place item update is not allowed. [#9549]

• Ensured that inserting np.ma.masked (or any other value with a mask) into a MaskedColumn causes a masked entry to be inserted. [#9623]

• Fixed a bug that caused an exception when initializing a MaskedColumn from another MaskedColumn that has a structured dtype. [#9651]

astropy.tests

• The plugin that handles the custom header in the test output has been moved to the pytest-astropy-header plugin package. See the README at for information about using this new plugin. [#9214]

astropy.time

• Added a new time format ymdhms for representing times via year, month, day, hour, minute, and second attributes. [#7644]

• TimeDelta gained a to_value method, so that it becomes easier to use it wherever a Quantity with units of time could be used. [#8762]

• Made scalar Time and TimeDelta objects hashable based on JD, time scale, and location attributes. [#8912]

• Improved error message when bad input is used to initialize a Time or TimeDelta object and the format is specified. [#9296]

• Allow numeric time formats to be initialized with numpy longdouble, Decimal instances, and strings. One can select just one of these using in_subfmt. The output can be similarly set using out_subfmt. [#9361]

• Introduce a new .to_value() method for Time (and adjusted the existing method for TimeDelta) so that one can get values in a given format and possible subfmt (e.g., to_value('mjd', 'str'). [#9361]

• Prevent unnecessary ERFA warnings when sorting Time objects. [#9545]

astropy.timeseries

• Adding epoch_phase, wrap_phase and normalize_phase keywords to TimeSeries.fold() to control the phase of the epoch and to return normalized phase rather than time for the folded TimeSeries. [#9455]

astropy.uncertainty

• Distribution was rewritten such that it deals better with subclasses. As a result, Quantity distributions now behave correctly with to methods yielding new distributions of the kind expected for the starting distribution, and to_value yielding NdarrayDistribution instances. [#9429, #9442]

• The pdf_* properties that were used to calculate statistical properties of Distrubution instances were changed into methods. This allows one to pass parameters such as ddof to pdf_std and pdf_var (which generally should equal 1 instead of the default 0), and reflects that these are fairly involved calculations, not just “properties”. [#9613]

astropy.units

• Support for unicode parsing. Currently supported are superscripts, Ohm, Ångström, and the micro-sign. [#9348]

• Accept non-unit type annotations in @quantity_input. [#8984]

• For numpy 1.17 and later, the new __array_function__ protocol is used to ensure that all top-level numpy functions interact properly with Quantity, preserving units also in operations like np.concatenate. [#8808]

• Add equivalencies for surface brightness units to spectral_density. [#9282]

astropy.utils

• astropy.utils.data.download_file and astropy.utils.data.get_readable_fileobj now provides an http_headers keyword to pass in specific request headers for the download. It also now defaults to providing User-Agent: Astropy and Accept: */* headers. The default User-Agent value can be set with a new astropy.data.conf.default_http_user_agent configuration item. [#9508, #9564]

• Added a new astropy.utils.misc.unbroadcast function which can be used to return the smallest array that can be broadcasted back to the initial array. [#9209]

• The specific IERS Earth rotation parameter table used for time and coordinate transformations can now be set, either in a context or per session, using astropy.utils.iers.earth_rotation_table. [#9244]

• Added export_cache and import_cache to permit transporting downloaded data to machines with no Internet connection. Several new functions are available to investigate the cache contents; e.g., check_download_cache can be used to confirm that the persistent cache has not become damaged. [#9182]

• A new astropy.utils.iers.LeapSeconds class has been added to track leap seconds. [#9365]

astropy.visualization

• Added a new time_support context manager/function for making it easy to plot and format Time objects in Matplotlib. [#8782]

• Added support for plotting any WCS compliant with the generalized (APE 14) WCS API with WCSAxes. [#8885, #9098]

• Improved display of information when inspecting WCSAxes.coords. [#9098]

• Improved error checking for the slices= argument to WCSAxes. [#9098]

• Added support for more solar frames in WCSAxes. [#9275]

• Add support for one dimensional plots to WCSAxes. [#9266]

• Add a get_format_unit to wcsaxes.CoordinateHelper. [#9392]

• WCSAxes now, by default, sets a default label for plot axes which is the WCS physical type (and unit) for that axis. This can be disabled using the coords[i].set_auto_axislabel(False) or by explicitly setting an axis label. [#9392]

• Fixed the display of tick labels when plotting all sky images that have a coord_wrap less than 360. [#9542]

astropy.wcs

• Added a astropy.wcs.wcsapi.pixel_to_pixel function that can be used to transform pixel coordinates in one dataset with a WCS to pixel coordinates in another dataset with a different WCS. This function is designed to be efficient when the input arrays are broadcasted views of smaller arrays. [#9209]

• Added a local_partial_pixel_derivatives function that can be used to determine a matrix of partial derivatives of each world coordinate with respect to each pixel coordinate. [#9392]

• Updated wcslib to v6.4. [#9125]

• Improved the SlicedLowLevelWCS class in astropy.wcs.wcsapi to avoid storing chains of nested SlicedLowLevelWCS objects when applying multiple slicing operations in turn. [#9210]

• Added a wcs_info_str function to astropy.wcs.wcsapi to show a summary of an APE-14-compliant WCS as a string. [#8546, #9207]

• Added two new optional attributes to the APE 14 low-level WCS: pixel_axis_names and world_axis_names. [#9156]

• Updated the WCS class to now correctly take and return Time objects in the high-level APE 14 API (e.g. pixel_to_world. [#9376]

• SlicedLowLevelWCS now raises IndexError rather than ValueError on an invalid slice. [#9067]

• Added fit_wcs_from_points function to astropy.wcs.utils. Fits a WCS object to set of matched detector/sky coordinates. [#9469]

• Fix various bugs in SlicedLowLevelWCS when the WCS being sliced was one dimensional. [#9693]

API Changes

astropy.constants

• Deprecated set_enabled_constants context manager. Use astropy.physical_constants and astropy.astronomical_constants. [#9025]

astropy.convolution

• Removed the deprecated keyword argument interpolate_nan from convolve_fft. [#9356]

• Removed the deprecated keyword argument stddev from Gaussian2DKernel. [#9356]

• Deprecated and renamed MexicanHat1DKernel and MexicanHat2DKernel to RickerWavelet1DKernel and RickerWavelet2DKernel. [#9445]

astropy.coordinates

• Removed the recommended_units attribute from Representations; it was deprecated since 3.0. [#8892]

• Removed the deprecated frame attribute classes, FrameAttribute, TimeFrameAttribute, QuantityFrameAttribute, CartesianRepresentationFrameAttribute; deprecated since 3.0. [#9326]

• Removed longitude and latitude attributes from EarthLocation; deprecated since 2.0. [#9326]

• The DifferentialAttribute for frame classes now passes through any input to the allowed_classes if only one allowed class is specified, i.e. this now allows passing a quantity in for frame attributes that use DifferentialAttribute. [#9325]

• Removed the deprecated galcen_ra and galcen_dec attributes from the Galactocentric frame. [#9346]

astropy.extern

• Remove the bundled six module. [#8315]

astropy.io.ascii

• Masked column handling has changed, see astropy.table entry below. [#8789]

astropy.io.misc

• Masked column handling has changed, see astropy.table entry below. [#8789]

• Removed deprecated usecPickle kwarg from fnunpickle and fnpickle. [#8890]

astropy.io.fits

• Masked column handling has changed, see astropy.table entry below. [#8789]

• io.fits.Header has been made safe for subclasses for copying and slicing. As a result of this change, the private subclass CompImageHeader now always should be passed an explicit image_header. [#9229]

• Removed the deprecated tolerance option in fitsdiff and io.fits.diff classes. [#9520]

• Removed deprecated keyword arguments for CompImageHDU: compressionType, tileSize, hcompScale, hcompSmooth, quantizeLevel. [#9520]

astropy.io.votable

• Changed pedantic argument to verify and change it to have three string-based options (ignore, warn, and exception) instead of just being a boolean. In addition, changed default to ignore, which means that warnings will not be shown by default when loading VO tables. [#8715]

astropy.modeling

• Eliminates support for compound classes (but not compound instances!) [#8769]

• Slicing compound models more restrictive. [#8769]

• Shape of parameters now includes n_models as dimension. [#8769]

• Parameter instances now hold values instead of models. [#8769]

• Compound model parameters now share instance and value with constituent models. [#8769]

• No longer possible to assign slices of parameter values to model parameters attribute (it is possible to replace it with a complete array). [#8769]

• Many private attributes and methods have changed (see documentation). [#8769]

• Deprecated BlackBody1D model and blackbody_nu and blackbody_lambda functions. [#9282]

• The deprecated rotations.rotation_matrix_from_angle was removed. [#9363]

• Deprecated and renamed MexicanHat1D and MexicanHat2D to RickerWavelet1D and RickerWavelet2D. [#9445]

• Deprecated modeling.utils.ExpressionTree. [#9576]

astropy.stats

• Removed the iters keyword from sigma clipping stats functions. [#8948]

• Renamed the a parameter to data in biweight stat functions. [#8948]

• Renamed the a parameter to data in median_absolute_deviation. [#9011]

• Renamed the conflevel keyword to confidence_level in poisson_conf_interval. Usage of conflevel now issues AstropyDeprecationWarning. [#9408]

• Renamed the conf keyword to confidence_level in binom_conf_interval and binned_binom_proportion. Usage of conf now issues AstropyDeprecationWarning. [#9408]

• Renamed the conf_lvl keyword to confidence_level in jackknife_stats. Usage of conf_lvl now issues AstropyDeprecationWarning. [#9408]

astropy.table

• The handling of masked columns in the Table class has changed in a way that may impact program behavior. Now a Table with masked=False may contain both Column and MaskedColumn objects, and adding a masked column or row to a table no longer “upgrades” the table and columns to masked. This means that tables with masked data which are read via Table.read() will now always have masked=False, though specific columns will be masked as needed. Two new table properties has_masked_columns and has_masked_values were added. See the Masking change in astropy 4.0 section within for details. [#8789]

• Table operation functions such as join, vstack, hstack, etc now always return a table with masked=False, though the individual columns may be masked as necessary. [#8957]

• Changed implementation of Table.add_column() and Table.add_columns() methods. Now it is possible add any object(s) which can be converted or broadcasted to a valid column for the table. Table.__setitem__ now just calls add_column. [#8933]

• Changed default table configuration setting replace_warnings from ['slice'] to []. This removes the default warning when replacing a table column that is a slice of another column. [#9144]

• Removed the non-public method astropy.table.np_utils.recarray_fromrecords. [#9165]

astropy.tests

• In addition to DeprecationWarning, now FutureWarning and ImportWarning would also be turned into exceptions. [#8506]

• warnings_to_ignore_by_pyver option in enable_deprecations_as_exceptions() has changed. Please refer to API documentation. [#8506]

• Default settings for warnings_to_ignore_by_pyver are updated to remove very old warnings that are no longer relevant and to add a new warning caused by pytest-doctestplus. [#8506]

astropy.time

• Time.get_ut1_utc now uses the auto-updated IERS_Auto by default, instead of the bundled IERS_B file. [#9226]

• Time formats that do not use val2 now raise ValueError instead of silently ignoring a provided value. [#9373]

• Custom time formats can now accept floating-point types with extended precision. Existing time formats raise exceptions rather than discarding extended precision through conversion to ordinary floating-point. [#9368]

• Time formats (implemented in subclasses of TimeFormat) now have their input and output routines more thoroughly validated, making it more difficult to create damaged Time objects. [#9375]

• The TimeDelta.to_value() method now can also take the format name as its argument, in which case the value will be calculated using the TimeFormat machinery. For this case, one can also pass a subfmt argument to retrieve the value in another form than float. [#9361]

astropy.timeseries

• Keyword midpoint_epoch is renamed to epoch_time. [#9455]

astropy.uncertainty

• Distribution was rewritten such that it deals better with subclasses. As a result, Quantity distributions now behave correctly with to methods yielding new distributions of the kind expected for the starting distribution, and to_value yielding NdarrayDistribution instances. [#9442]

astropy.units

• For consistency with ndarray, scalar Quantity.value will now return a numpy scalar rather than a python one. This should help keep track of precision better, but may lead to unexpected results for the rare cases where numpy scalars behave differently than python ones (e.g., taking the square root of a negative number). [#8876]

• Removed the magnitude_zero_points module, which was deprecated in favour of astropy.units.photometric since 3.1. [#9353]

• EquivalentUnitsList now has a _repr_html_ method to output a HTML table on a call to find_equivalent_units in Jupyter notebooks. [#9495]

astropy.utils

• download_file and related functions now accept a list of fallback sources, and they are able to update the cache at the user’s request. [#9182]

• Allow astropy.utils.console.ProgressBarOrSpinner.map and .map_unordered to take an argument multiprocessing_start_method to control how subprocesses are started; the different methods (fork, spawn, and forkserver) have different implications in terms of security, efficiency, and behavioural anomalies. The option is useful in particular for cross-platform testing because Windows supports only spawn while Linux defaults to fork. [#9182]

• All operations that act on the astropy download cache now take an argument pkgname that allows one to specify which package’s cache to use. [#8237, #9182]

• Removed deprecated funcsigs and futures from astropy.utils.compat. [#8909]

• Removed the deprecated astropy.utils.compat.numpy module. [#8910]

• Deprecated InheritDocstrings as it is natively supported by Sphinx 1.7 or higher. [#8881]

• Deprecated astropy.utils.timer module, which has been moved to astroquery.utils.timer and will be part of astroquery 0.4.0. [#9038]

• Deprecated astropy.utils.misc.set_locale function, as it is meant for internal use only. [#9471]

• The implementation of data_info.DataInfo has changed (for a considerable performance boost). Generally, this should not affect simple subclasses, but because the class now uses __slots__ any attributes on the class have to be explicitly given a slot. [#8998]

• IERS tables now use nan to mark missing values (rather than 1e20). [#9226]

astropy.visualization

• The default clip value is now False in ImageNormalize. [#9478]

• The default clip value is now False in simple_norm. [#9698]

• Infinite values are now excluded when calculating limits in ManualInterval and MinMaxInterval. They were already excluded in all other interval classes. [#9480]

Bug Fixes

astropy.convolution

• Fixed nan_treatment='interpolate' option to convolve_fft to properly take into account fill_value. [#8122]

astropy.coordinates

• The QuantityAttribute class now supports a None default value if a unit is specified. [#9345]

• When Representation classes with the same name are defined, this no longer leads to a ValueError, but instead to a warning and the removal of both from the name registry (i.e., one either has to use the class itself to set, e.g., representation_type, or refer to the class by its fully qualified name). [#8561]

astropy.io.fits

• Implemented skip (after warning) of header cards with reserved keywords in table_to_hdu. [#9390]

• Add AstropyDeprecationWarning to read_table_fits when hdu= is selected, but does not match single present table HDU. [#9512]

astropy.io.votable

• Address issue #8995 by ignoring BINARY2 null mask bits for string values on parsing a VOTable. In this way, the reader should never create masked values for string types. [#9057]

• Corrected a spurious warning issued for the value attribute of the <OPTION> element in VOTable, as well as a test that erroneously treated the warning as acceptable. [#9470]

astropy.nddata

• Cutout2D will now get the WCS from its first argument if that argument has with WCS property. [#9492]

• overlap_slices will now raise a ValueError if the input position contains any non-finite values (e.g. NaN or inf). [#9648]

astropy.stats

• Fixed a bug where bayesian_blocks returned a single edge. [#8560]

• Fixed input data type validation for bayesian_blocks to work int arrays. [#9513]

astropy.table

• Fix bug where adding a column consisting of a list of masked arrays was dropping the masks. [#9048]

• Quantity columns with custom units can now round-trip via FITS tables, as long as the custom unit is enabled during reading (otherwise, the unit will become an UnrecognizedUnit). [#9015]

• Fix bug where string values could be truncated when inserting into a Column or MaskedColumn, or when adding or inserting a row containing string values. [#9559]

astropy.time

• Fix bug when Time object is created with only masked elements. [#9624]

• Fix inaccuracy when converting between TimeDelta and datetime.timedelta. [#9679]

astropy.units

• Ensure that output from test functions of and comparisons between quantities can be stored into pre-allocated output arrays (using out=array) [#9273]

astropy.utils

• For the default IERS_Auto table, which combines IERS A and B values, the IERS nutation parameters “dX_2000A” and “dY_2000A” are now also taken from the actual IERS B file rather than from the B values stored in the IERS A file. Any differences should be negligible for any practical application, but this may help exactly reproducing results. [#9237]

astropy.visualization

• Calling WCSAxes.set_axis_off() now correctly turns off drawing the Axes. [#9411]

• Fix incorrect transformation behavior in WCSAxes.plot_coord and correctly handle when input coordinates are not already in spherical representations. [#8927]

• Fixed ImageNormalize so that when it is initialized without data it will still use the input interval class. [#9698]

• Fixed ImageNormalize to handle input data with non-finite values. [#9698]

astropy.wcs

• Fix incorrect value returned by wcsapi.HighLevelWCSWrapper.axis_correlation_matrix. [#9554]

• Fix NaN-masking of world coordinates when some but not all of the coordinates were flagged as invalid by WCSLIB. This occurred for example with WCS with >2 dimensions where two of the dimensions were celestial coordinates and pixel coordinates outside of the ‘sky’ were converted to world coordinates - previously all world coordinates were masked even if uncorrelated with the celestial axes, but this is no longer the case. [#9688]

• The default WCS to celestial frame mapping for world coordinate systems that specify TLON and TLAT coordinates will now return an ITRS frame with the representation class set to SphericalRepresentation. This fixes a bug that caused WCS.pixel_to_world to raise an error for such world coordinate systems. [#9609]

• FITSWCSAPIMixin now returns tuples not lists from pixel_to_world and world_to_pixel. [#9678]

Other Changes and Additions

• Versions of Python <3.6 are no longer supported. [#8955]

• Matplotlib 2.1 and later is now required. [#8787]

• Versions of Numpy <1.16 are no longer supported. [#9292]

• Updated the bundled CFITSIO library to 3.470. See cextern/cfitsio/docs/changes.txt for additional information. [#9233]

• The bundled ERFA was updated to version 1.7.0. This is based on SOFA 20190722. This includes a fix to avoid precision loss for negative JDs, and also includes additional routines to allow updates to the leap-second table. [#9323, #9734]

• The default server for the IERS data files has been updated to reflect long-term downtime of the canonical USNO server. [#9487, #9508]

Version 3.2.3 (2019-10-27)

Other Changes and Additions

• Updated IERS A URLs due to USNO prolonged maintenance. [#9443]

Version 3.2.2 (2019-10-07)

Bug fixes

astropy.convolution

• Fixed a bug in discretize_oversample_1D/2D() from astropy.convolution.utils, which might occasionally introduce unexpected oversampling grid dimensions due to a numerical precision issue. [#9293]

• Fixed a bug [#9168] where having a kernel defined using unitless astropy quantity objects would result in a crash [#9300]

astropy.coordinates

• Fix concatenation of representations for cases where the units were different. [#8877]

• Check for NaN values in catalog and match coordinates before building and querying the KDTree for coordinate matching. [#9007]

• Fix sky coordinate matching when a dimensionless distance is provided. [#9008]

• Raise a faster and more meaningful error message when differential data units are not compatible with a containing representation’s units. [#9064]

• Changed the timescale in ICRS to CIRS from ‘tdb’ to ‘tt’ conversion and vice-versa, as the erfa function that gets called in the process, pnm06a accepts time in TT. [#9079]

astropy.io.ascii

• Fixed the fast reader when used in parallel and with the multiprocessing ‘spawn’ method (which is the default on MacOS X with Python 3.8 and later), and enable parallel fast reader on Windows. [#8853]

astropy.io.fits

• Fixes bug where an invalid TRPOS<n> keyword was being generated for FITS time column when no location was available. [#8784]

• Fixed a wrong exception when converting a Table with a unit that is not FITS compliant and not convertible to a string using format='fits'. [#8906]

• Fixed an issue with A3DTABLE extension that could not be read. [#9012]

• Fixed the update of the header when creating GroupsHDU from data. [#9216]

astropy.nddata

• Fix to add_array, which now accepts array_small having dimensions equal to array_large, instead of only allowing smaller sizes of arrays. [#9118]

astropy.stats

• Fixed median_absolute_deviation for the case where ignore_nan=True and an input masked array contained both NaNs and infs. [#9307]

astropy.table

• Comparisons between Column instances and Quantity will now correctly take into account the unit (as was already the case for regular operations such as addition). [#8904]

astropy.time

• Allow Time to be initialized with an empty value for all formats. [#8854]

• Fixed a troubling bug in which Time could loose precision, with deviations of 300 ns. [#9328]

astropy.timeseries

• Fixed handling of Quantity input data for all methods of LombScarge.false_alarm_probabilty. [#9246]

astropy.units

• Allow conversion of Column with logarithmic units to a suitable Quantity subclass if subok=True. [#9188]

• Ensured that we simplify powers to smaller denominators if that is consistent within rounding precision. [#9267]

• Ensured that the powers shown in a unit’s repr are always correct, not oversimplified. [#9267]

astropy.utils

• Fixed find_api_page access by using custom request headers and HTTPS when version is specified. [#9032]

• Make download_file (and by extension get_readable_fileobj and others) check the size of downloaded files against the size claimed by the server. [#9302]

• Fix find_current_module so that it works properly if astropy is being used inside a bundle such as that produced by PyInstaller. [#8845]

• Fix path to renamed classes, which previously included duplicate path/module information under certain circumstances. [#8845]

astropy.visualization

• Silence numpy runtime warnings in WCSAxes when drawing grids. [#8882]

astropy.wcs

• Fixed equality test between cunit where the first element was equal but the following elements differed. [#9154]

• Fixed a crash while loading a WCS from headers containing duplicate SIP keywords. [#8893]

• Fixed a possible buffer overflow when using too large negative indices for cunit or ctype [#9151]

• Fixed reference counting in WCSBase.__init__ [#9166]

• Fix SlicedLowLevelWCS world_to_pixel_values and pixel_to_world_values when inputs need broadcasting to the same shape. (i.e. when one input is sliced out) [#9250]

• Fixed a bug that caused WCS.array_shape, WCS.pixel_shape and WCS.pixel_bounds to be incorrect after using WCS.sub. [#9095]

Other Changes and Additions

• Fixed a bug that caused files outside of the astropy module directory to be included as package data, resulting in some cases in errors when doing repeated builds. [#9039]

Version 3.2.1 (2019-06-14)

Bug fixes

astropy.io.fits

• Avoid reporting a warning with BinTableHDU.from_columns with keywords that are not provided by the user. [#8838]

• Fix Header.fromfile to work on FITS files. [#8713]

• Fix reading of empty BinTableHDU when stored in a gzip-compressed file. [#8848]

astropy.table

• Fix a problem where mask was dropped when creating a MaskedColumn from a list of MaskedArray objects. [#8826]

astropy.wcs

• Added None to be displayed as a world_axis_physical_types in the WCS repr, as None values are now supported in APE14. [#8811]

Version 3.2 (2019-06-10)

New Features

astropy.constants

• Add CODATA 2018 constants but not make them default because the redefinition of SI units that will follow has not been implemented yet. [#8595]

astropy.coordinates

• New BarycentricMeanEcliptic, HeliocentricTrueEcliptic and GeocentricTrueEcliptic frames. The ecliptic frames are no longer considered experimental. [#8394]

• The default time scale for epochs like ‘J2000’ or ‘B1975’ is now “tt”, which is the correct one for ‘J2000’ and avoids leap-second warnings for epochs in the far future or past. [#8600]

astropy.extern

• Bundled six now emits AstropyDeprecationWarning. It will be removed in 4.0. [#8323]

astropy.io.ascii

• IPAC tables now output data types of float instead of double, or int instead of long, based on the column dtype.itemsize. [#8216]

• Update handling of MaskedColumn columns when using the ‘data_mask’ serialization method. This can make writing ECSV significantly faster if the data do not actually have any masked values. [#8447]

• Fixed a bug that caused newlines to be incorrect when writing out ASCII tables on Windows (they were \r\r\n instead of \r\n). [#8659]

astropy.io.misc

• Implement serialization of TimeDelta in ASDF. [#8285]

• Implement serialization of EarthLocation in ASDF. [#8286]

• Implement serialization of SkyCoord in ASDF. [#8284]

• Support serialization of Astropy tables with mixin columns in ASDF. [#8337]

• No warnings when reading HDF5 files with only one table and no path= argument [#8483]

• The HDF5 writer will now create a default table instead of raising an exception when path= is not specified and when writing to empty/new HDF5 files. [#8553]

astropy.io.fits

• Optimize parsing of cards within the Header class. [#8428]

• Optimize the parsing of headers to get the structural keywords that are needed to find extensions. Thanks to this, getting a random HDU from a file with many extensions is much faster than before, in particular when the extension headers contain many keywords. [#8502]

• Change behavior of FITS undefined value in Header such that None is used in Python to represent FITS undefined when using dict interface. Undefined can also be assigned and is translated to None. Previously setting a header card value to None resulted in an empty string field rather than a FITS undefined value. [#8572]

• Allow Header.fromstring and Card.fromstring to accept bytes. [#8707]

astropy.io.registry

• Implement Table reader and writer for ASDF. [#8261]

• Implement Table reader and writer methods to wrap pandas I/O methods for CSV, Fixed width format, HTML, and JSON. [#8381]

• Add help() and list_formats() methods to unified I/O read and write methods. For example Table.read.help() gives help on available Table read formats and Table.read.help('fits') gives detailed help on the arguments for reading FITS table file. [#8255]

astropy.table

• Initializing a table with Table(rows=...), if the first item is an OrderedDict, now uses the column order of the first row. [#8587]

• Added new pprint_all() and pformat_all() methods to Table. These two new methods print the entire table by default. [#8577]

• Removed restriction of initializing a Table from a dict with copy=False. [#8541]

• Improved speed of table row access by a factor of about 2-3. Improved speed of Table len() by a factor of around 3-10 (depending on the number of columns). [#8494]

• Improved the Table - pandas DataFrame interface (to_pandas() and from_pandas()). Mixin columns like Time and Quantity can now be converted to pandas by flattening the columns as necessary to plain columns. Time and TimeDelta columns get converted to corresponding pandas date or time delta types. The DataFrame index is now handled in the conversion methods. [#8247]

• Added rename_columns method to rename multiple columns in one call. [#5159, #8070]

• Improved Table performance by reducing unnecessary calls to copy and deepcopy, especially as related to the table and column meta attributes. Changed the behavior when slicing a table (either in rows or with a list of column names) so now the sliced output gets a light (key-only) copy of meta instead of a deepcopy. Changed the Table.meta class-level descriptor so that assigning directly to meta, e.g. tbl.meta = new_meta no longer does a deepcopy and instead just directly assigns the new_meta object reference. Changed Table initialization so that input meta is copied only if copy=True. [#8404]

• Improved Table slicing performance with internal implementation changes related to column attribute access and certain input validation. [#8493]

• Added reverse argument to the sort and argsort methods to allow sorting in reverse order. [#8528]

• Improved Table.sort() performance by removing self[keys] from code which is creating deep copies of meta attribute and adding a new keyword names in get_index() to get index by using a list or tuple containing names of columns. [#8570]

• Expose represent_mixins_as_columns as a public function in the astropy.table subpackage. This previously-private function in the table.serialize module is used to represent mixin columns in a Table as one or more plain Column objects. [#7729]

astropy.timeseries

• Added a new astropy.timeseries sub-package to represent and manipulate sampled and binned time series. [#8540]

• The BoxLeastSquares and LombScargle classes have been moved to astropy.timeseries.periodograms from astropy.stats. [#8591]

• Added the ability to provide absolute Time objects to the BoxLeastSquares and LombScargle periodogram classes. [#8599]

• Added model inspection methods (model_parameters(), design_matrix(), and offset()) to astropy.timeseries.LombScargle class [#8397].

astropy.units

• Quantity overrides of ndarray methods such as sum, min, max, which are implemented via reductions, have been removed since they are dealt with in Quantity.__array_ufunc__. This should not affect subclasses, but they may consider doing similarly. [#8316] Note that this does not include methods that use more complicated python code such as mean, std and var. [#8370]

astropy.visualization

• Added CompositeStretch, which inherits from CompositeTransform and also BaseStretch so that it can be used with ImageNormalize. [#8564]

• Added a log_a argument to the simple_norm method. Similar to the exposing of the asinh_a argument for AsinhStretch, the new log_a argument is now exposed for LogStretch. [#8436]

astropy.wcs

• WCSLIB was updated to v 6.2. This adds support for time-related WCS keywords (WCS Paper VII). FITS headers containing Time axis are parsed and the axis is included in the WCS object. [#8592]

• The OBSGEO attribute as expanded to 6 members - XYZLBH. [#8592]

• Added a new class SlicedLowLevelWCS in astropy.wcs.wcsapi that can be used to slice any WCS that conforms to the BaseLowLevelWCS API. [#8546]

• Updated implementation of WCS.__getitem__ and WCS.slice to now return a SlicedLowLevelWCS rather than raising an error when reducing the dimensionality of the WCS. [#8546]

API Changes

astropy.coordinates

• QuantityAttribute no longer has a default value for default. The previous value of None was misleading as it always was an error. [#8450]

• The default J2000 has been changed to use be January 1, 2000 12:00 TT instead of UTC. This is more in line with convention. [#8594]

astropy.io.ascii

• IPAC tables now output data types of float instead of double, or int instead of long, based on the column dtype.itemsize. [#8216]

astropy.io.misc

• Unit equivalencies can now be serialized to ASDF. [#8252]

astropy.modeling

• Composition of model classes is deprecated and will be removed in 4.0. Composition of model instances remain unaffected. [#8234, #8408]

astropy.stats

• The BoxLeastSquares and LombScargle classes have been moved to the astropy.timeseries.periodograms module and will now emit a deprecation warning when imported from astropy.stats. [#8591]

astropy.table

• Converting an empty table to an array using as_array method now returns an empty array instead of None. [#8647]

• Changed the behavior when slicing a table (either in rows or with a list of column names) so now the sliced output gets a light (key-only) copy of meta instead of a deepcopy. Changed the Table.meta class-level descriptor so that assigning directly to meta, e.g. tbl.meta = new_meta no longer does a deepcopy and instead just directly assigns the new_meta object reference. Changed Table initialization so that input meta is copied only if copy=True. [#8404]

• Added a keyword names in Table.as_array(). If provided this specifies a list of column names to include for the returned structured array. [#8532]

astropy.tests

• Removed pytest_plugins as they are completely broken for pytest>=4. [#7786]

• Removed the astropy.tests.plugins.config plugin and removed the --astropy-config-dir and --astropy-cache-dir options from testing. Please use caching functionality that is natively in pytest. [#7787, #8489]

astropy.time

• The default time scale for epochs like ‘J2000’ or ‘B1975’ is now “tt”, which is the correct one for ‘J2000’ and avoids leap-second warnings for epochs in the far future or past. [#8600]

astropy.units

• Unit equivalencies can now be introspected. [#8252]

astropy.wcs

• The world_to_pixel, world_to_array_index*, pixel_to_world* and array_index_to_world* methods now all consistently return scalars, arrays, or objects not wrapped in a one-element tuple/list when only one scalar, array, or object (as was previously already the case for WCS.pixel_to_world and WCS.array_index_to_world). [#8663]

astropy.utils

• It is now possible to control the number of cores used by ProgressBar.map by passing a positive integer as the multiprocess keyword argument. Use True to use all cores. [#8083]

Bug Fixes

astropy.coordinates

• BarycentricTrueEcliptic, HeliocentricTrueEcliptic and GeocentricTrueEcliptic now use the correct transformation (including nutation), whereas the new *MeanEcliptic classes use the nutation-free transformation. [#8394]

• Representations with float32 coordinates can now be transformed, although the output will always be float64. [#8759]

• Fixed bug that prevented using differentials with HCRS<->ICRS transformations. [#8794]

astropy.io.ascii

• Fixed a bug where an exception was raised when writing a table which includes mixin columns (e.g. a Quantity column) and the output format was specified using the formats keyword. [#8681]

astropy.io.misc

• Fixed bug in ASDF tag that inadvertently introduced dependency on pytest. [#8456]

astropy.modeling

• Fixed slowness for certain compound models consisting of large numbers of multi-input models [#8338, #8349]

• Fixed bugs in fitting of compound models with units. [#8369]

astropy.nddata

• Fixed bug in reading multi-extension FITS files written by earlier versions of CCDData. [#8534]

• Fixed two errors in the way CCDData handles FITS files with WCS in the header. Some of the WCS keywords that should have been removed from the header were not, potentially leading to FITS files with inconsistent WCS. [#8602]

astropy.table

• Fixed a bug when initializing from an empty list: Table([]) no longer results in a crash. [#8647]

• Fixed a bug when initializing from an existing Table. In this case the input meta argument was being ignored. Now the input meta, if supplied, will be used as the meta for the new Table. [#8404]

• Fix the conversion of bytes values to Python str with Table.tolist. [#8739]

astropy.time

• Fixed a number of issues to ensure a consistent output type resulting from multiplication or division involving a TimeDelta instance. The output is now always a TimeDelta if the result is a time unit (like u.s or u.d), otherwise it will be a Quantity. [#8356]

• Multiplication between two TimeDelta instances is now possible, resulting in a Quantity with units of time squared (division already correctly resulted in a dimensionless Quantity). [#8356]

• Like for comparisons, addition, and subtraction of Time instances with with non-time instances, multiplication and division of TimeDelta instances with incompatible other instances no longer immediately raise an UnitsError or TypeError (depending on the other instance), but rather go through the regular Python mechanism of TimeDelta returning NotImplemented (which will lead to a regular TypeError unless the other instance can handle TimeDelta). [#8356]

• Corrected small rounding errors that could cause the jd2 values in Time to fall outside the range of -0.5 to 0.5. [#8763]

astropy.units

• Added a Quantity.to_string method to add flexibility to the string formatting of quantities. It produces unadorned or LaTeX strings, and accepts two different sets of delimiters in the latter case: inline and display. [#8313]

• Ensure classes that mimic quantities by having a unit attribute and/or to and to_value methods can be properly used to initialize Quantity or set Quantity instance items. [#8535]

• Add support for << to create logarithmic units. [#8290]

• Add support for the clip ufunc, which in numpy 1.17 is used to implement np.clip. As part of that, remove the Quantity.clip method under numpy 1.17. [#8747]

• Fix parsing of numerical powers in FITS-compatible units. [#8251]

astropy.wcs

• Added a PyUnitListProxy_richcmp method in UnitListProxy class to enable WCS.wcs.cunit equality testing. It helps to check whether the two instances of WCS.wcs.cunit are equal or not by comparing the data members of UnitListProxy class [#8480]

• Fixed SlicedLowLevelWCS when array_shape is None. [#8649]

• Do not attempt to delete repeated distortion keywords multiple times when loading distortions with _read_distortion_kw and _read_det2im_kw. [#8777]

Other Changes and Additions

• Update bundled expat to 2.2.6. [#8343]

• Added instructions for uploading releases to Zenodo. [#8395]

• The bug fixes to the behaviour of TimeDelta for multiplcation and division, which ensure that the output is now always a TimeDelta if the result is a time unit (like u.s or u.d) and otherwise a Quantity, imply that sometimes the output type will be different than it was before. [#8356]

• For types unrecognized by TimeDelta, multiplication and division now will consistently return a TypeError if the other instance cannot handle TimeDelta (rather than UnitsError or TypeError depending on presumed abilities of the other instance). [#8356]

• Multiplication between two TimeDelta instances will no longer result in an OperandTypeError, but rather result in a Quantity with units of time squared (division already correctly resulted in a dimensionless Quantity). [#8356]

• Made running the tests insensitive to local user configuration when running the tests in parallel mode or directly with pytest. [#8727]

• Added a narrative style guide to the documentation for contributor reference. [#8588]

• Ensure we call numpy equality functions in a way that reduces the number of DeprecationWarning. [#8755]

Installation

• We now require setuptools 30.3.0 or later to install the core astropy package. [#8240]

• We now define groups of dependencies that can be installed with pip, e.g. pip install astropy[all] (to install all optional dependencies). [#8198]

Version 3.1.2 (2019-02-23)

Bug fixes

astropy.coordinates

• Convert the default of QuantityAttribute, thereby catching the error case case of it being set to None at attribute creation, and giving a more useful error message in the process. [#8300]

astropy.cosmology

• Fix elliptic analytical solution for comoving distance. Only relevant for non-flat cosmologies without radiation and Om0 > Ode0. [#8391]

astropy.modeling

• Fixed slowness for certain compound models consisting of large numbers of multi-input models [#8338, #8349]

astropy.visualization.wcsaxes

• Fix a bug that caused an error when passing an array with all values the same to contour or contourf. [#8321]

• Fix a bug that caused contour and contourf to return None instead of the contour set. [#8321]

Version 3.1.1 (2018-12-31)

Bug fixes

astropy.io.ascii

• Fix error when writing out empty table. [#8279]

astropy.io.fits

• fitsdiff --ignore-hdus now prints input filenames in the diff report instead of <HDUList object at 0x1150f9778>. [#8295]

astropy.units

• Ensure correctness of units when raising to a negative power. [#8263]

• Fix with_H0 equivalency to use the correct direction of conversion. [#8292]

Version 3.1 (2018-12-06)

New Features

astropy.convolution

• convolve now accepts any array-like input, not just numpy.ndarray or lists. [#7303]

• convolve Now raises AstropyUserWarning if nan_treatment=’interpolate’ and preserve_nan=False and NaN values are present post convolution. [#8088]

astropy.coordinates

• The SkyCoord.from_name constructor now has the ability to create coordinate objects by parsing object catalogue names that have embedded J-coordinates. [#7830]

• The new function make_transform_graph_docs can be used to create a docstring graph from a custom TransformGraph object. [#7135]

• KDTree for catalog matching is now built with sliding midpoint rule rather than standard. In code, this means setting compact_nodes=False and balanced_tree=False in cKDTree. The sliding midpoint rule is much more suitable for catalog matching, and results in 1000x speedup in some cases. [#7324]

• Additional information about a site loaded from the Astropy sites registry is now available in EarthLocation.info.meta. [#7857]

• Added a concatenate_representations function to combine coordinate representation data and any associated differentials. [#7922]

• BaseCoordinateFrame will now check for a method named _astropy_repr_in_frame when constructing the string forms of attributes. Allowing any class to control how BaseCoordinateFrame represents it when it is an attribute of a frame. [#7745]

• Some rarely-changed attributes of frame classes are now cached, resulting in speedups (up to 50% in some cases) when creating new scalar frame or SkyCoord objects. [#7949, #5952]

• Added a directional_offset_by method to SkyCoord that computes a new coordinate given a coordinate, position angle, and angular separation [#5727]

astropy.cosmology

• The default cosmology has been changed from WMAP9 to Planck15. [#8123]

• Distance calculations with LambaCDM with no radiation (T_CMB0=0) are now 20x faster by using elliptic integrals for non-flat cases. [#7155]

• Distance calculations with FlatLambaCDM with no radiation (T_CMB0=0) are now 20x faster by using the hypergeometric function solution for this special case. [#7087]

• Age calculations with FlatLambdaCDM with no radiation (Tcmb0=0) are now 1000x faster by using analytic solutions instead of integrating. [#7117]

astropy.io.ascii

• Latex reader now ignores \toprule, \midrule, and \bottomrule commands. [#7349]

• Added the RST (Restructured-text) table format and the fast version of the RDB reader to the set of formats that are guessed by default. [#5578]

• The read trace (used primarily for debugging) now includes guess argument sets that were skipped entirely e.g. for not supporting user-supplied kwargs. All guesses thus removed from filtered_guess_kwargs are now listed as “Disabled” at the beginning of the trace. [#5578]

• Emit a warning when reading an ECSV file without specifying the format and without PyYAML installed. Previously this silently fell through to parsing as a basic format file and the file metadata was lost. [#7580]

• Optionally allow writing masked columns to ECSV with the mask explicitly specified as a separate column instead of marking masked elements with “” (empty string). This allows handling the case of a masked string column with “” data rows. [#7481]

astropy.io.misc

• Added support for saving all representation classes and many coordinate frames to the asdf format. [#7079]

• Added support for saving models with units to the asdf format. [#7237]

• Added a new character_as_bytes keyword to the HDF5 Table reading function to control whether byte string columns in the HDF5 file are left as bytes or converted to unicode. The default is to read as bytes (character_as_bytes=True). [#7024, #8017]

astropy.io.fits

• HDUList.pop() now accepts string and tuple extension name specifications. [#7236]

• Add an ignore_hdus keyword to FITSDiff to allow ignoring HDUs by NAME when diffing two FITS files [#7538]

• Optionally allow writing masked columns to FITS with the mask explicitly specified as a separate column instead of using the FITS standard of certain embedded null values (NaN for float, TNULL for integers). This can be used to work around limitations in the FITS standard. [#7481]

• All time coordinates can now be written to and read from FITS binary tables, including those with vectorized locations. [#7430]

• The fitsheader command line tool now supports a dfits+fitsort mode, and the dotted notation for keywords (e.g. ESO.INS.ID). [#7240]

• Fall back to reading arrays using mode=’denywrite’ if mode=’readonly’ fails when using memory-mapping. This solves cases on some platforms when the available address space was less than the file size (even when using memory mapping). [#7926]

astropy.modeling

• Add a Multiply model which preserves unit through evaluate, unlike Scale which is dimensionless. [#7210]

• Add a uses_quantity property to Model which allows introspection of if the Model can accept Quantity objects. [#7417]

• Add a separability_matrix function which returns the correlation matrix of inputs and outputs. [#7803]

• Fixed compatibility of JointFitter with the latest version of Numpy. [#7984]

• Add prior and posterior constraints to modeling parameters. These are not used by any current fitters, but are provided to allow user code to experiment with Bayesian fitters. [#7558]

astropy.nddata

• NDUncertainty objects now have a quantity attribute for simple conversion to quantities. [#7704]

• Add a bitmask module that provides functions for manipulating bitmasks and data quality (DQ) arrays. [#7944]

astropy.stats

• Add an astropy.stats.bls module with an implementation of the “box least squares” periodogram that is commonly used for discovering transiting exoplanets and eclipsing binaries. [#7391]

astropy.table

• Added support for full use of Time mixin column for join, hstack, and vstack table operations. [#6888]

• Added a new table index engine, SCEngine, based on the Sorted Containers package. [#7574]

• Add a new keyword argument serialize_method to Table.write to control how Time and MaskedColumn columns are written. [#7481]

• Allow mixin columns to be used in table group and unique functions. This applies to both the key columns and the other data columns. [#7712]

• Added support for stacking Column, mixin column (e.g. Quantity, Time) or column-like objects. [#7674]

• Added support for inserting a row into a Table that has Time or TimeDelta column(s). [#7897]

astropy.tests

• Added an option --readonly to the test command to change the permissions on the temporary installation location to read-only. [#7598]

astropy.time

• Allow array-valued Time object to be modified in place. [#6028]

• Added support for missing values (masking) to the Time class. [#6028]

• Added supper for a ‘local’ time scale (for free-running clocks, etc.), and round-tripping to the corresponding FITS time scale. [#7122]

• Added datetime.timedelta format class for TimeDelta. [#7441]

• Added strftime and strptime methods to Time class. These methods are similar to those in the Python standard library time package and provide flexible input and output formatting. [#7323]

• Added datetime64 format to the Time class to support working with numpy.datetime64 dtype arrays. [#7361]

• Add fractional second support for strftime and strptime methods of Time class. [#7705]

• Added an insert method to allow inserting one or more values into a Time or TimeDelta object. [#7897]

• Remove timescale from string version of FITS format time string. The timescale is not part of the FITS standard and should not be included. This change may cause some compatibility issues for code that relies on round-tripping a FITS format string with a timescale. Strings generated from previous versions of this package are still understood but a DeprecationWarning will be issued. [#7870]

astropy.uncertainty

• This sub-package was added as a “preview” (i.e. API unstable), containing the Distribution class and associated convenience functions. [#6945]

astropy.units

• Add complex numbers support for Quantity._repr_latex_. [#7676]

• Add thermodynamic_temperature equivalency to convert between Jy/sr and “thermodynamic temperature” for cosmology. [#7054]

• Add millibar unit. [#7863]

• Add maggy and nanomaggy unit, as well as associated zero_point_flux equivalency. [#7891]

• AB and ST are now enabled by default, and have alternate names ABflux and STflux. [#7891]

• Added littleh unit and associated with_H0 equivalency. [#7970]

astropy.visualization

• Added imshow_norm function, which combines imshow and creation of a ImageNormalize object. [#7785]

astropy.visualization.wcsaxes

• Add support for setting set_separator(None) in WCSAxes to use default separators. [#7570]

• Added two keyword argument options to CoordinateHelper.set_format_unit: decimal can be used to specify whether to use decimal formatting for the labels (by default this is False for degrees and hours and True otherwise), and show_decimal_unit can be used to determine whether the units should be shown for decimal labels. [#7318]

• Added documentation for transform= and coord_meta=. [#7698]

• Allow coord_meta= to optionally include format_unit=. [#7848]

• Add support for more rcParams related to the grid, ticks, and labels, and should work with most built-in Matplotlib styles. [#7961]

• Improved rendering of outward-facing ticks. [#7961]

• Add support for tick_params (which is a standard Matplotlib function/method) on both the WCSAxes class and the individual CoordinateHelper classes. Note that this is provided for compatibility with Matplotlib syntax users may be familiar with, but it is not the preferred way to change settings. Instead, methods such as set_ticks should be preferred. [#7969]

• Moved the argument exclude_overlapping from set_ticks to set_ticklabel. [#7969]

• Added a pad= argument to set_ticklabel to provide a way to control the padding between ticks and tick labels. [#7969]

• Added support for setting the tick direction in set_ticks using the direction= keyword argument. [#7969]

astropy.wcs

• Map ITRS frames to terrestrial WCS coordinates. This will make it possible to use WCSAxes to make figures that combine both celestial and terrestrial features. An example is plotting the coordinates of an astronomical transient over an all- sky satellite image to illustrate the position relative to the Earth at the time of the event. The ITRS frame is identified with WCSs that use the TLON- and TLAT- coordinate types. There are several examples of WCSs where this syntax is used to describe terrestrial coordinate systems: Section 7.4.1 of WCS in FITS “Paper II” and the WCSTools documentation. [#6990]

• Added the abstract base class for the low-level WCS API described in APE 14 (https://doi.org/10.5281/zenodo.1188875). [#7325]

• Add WCS.footprint_contains() function to check if the WCS footprint contains a given sky coordinate. [#7273]

• Added the abstract base class for the high-level WCS API described in APE 14 (https://doi.org/10.5281/zenodo.1188875). [#7325]

• Added the high-level wrapper class for low-level WCS objects as described in APE 14 (https://doi.org/10.5281/zenodo.1188875). [#7326]

• Added a new property WCS.has_distortion. [#7326]

• Deprecated _naxis1 and _naxis2 in favor of pixel_shape. [#7973]

• Added compatibility to wcslib version 6. [#8093]

API Changes

astropy.convolution

• kernel can now be a tuple. [#7561]

• Not technically an API changes, however, the doc string indicated that boundary=None was the default when actually it is boundary='fill'. The doc string has been corrected, however, someone may interpret this as an API change not realising that nothing has actually changed. [#7293]

• interpolate_replace_nans() can no longer accept the keyword argument preserve_nan. It is explicitly set to False. [#8088]

astropy.coordinates

• Fixed astropy.coordinates.concatenate to include velocity data in the concatenation. [#7922]

• Changed the name of the single argument to Frame.realize_frame() from the (incorrect) representation_type to data. [#7923]

• Negative parallaxes passed to Distance() now raise an error by default (allow_negative=False), or are converted to NaN values with a warning (allow_negative=True). [#7988]

• Negating a SphericalRepresentation object now changes the angular coordinates (by rotating 180º) instead of negating the distance. [#7988]

• Creation of new frames now generally creates copies of frame attributes, rather than inconsistently either copying or making references. [#8204]

• The frame class method is_equivalent_frame now checks for equality of components to determine if a frame is the same when it has frame attributes that are representations, rather than checking if they are the same object. [#8218]

astropy.io.ascii

• If a fast reader is explicitly selected (e.g. fast_reader='force') and options which are incompatible with the fast reader are provided (e.g. quotechar='##') then now a ParameterError exception will be raised. [#5578]

• The fast readers will now raise InconsistentTableError instead of CParserError if the number of data and header columns do not match. [#5578]

• Changed a number of ValueError exceptions to InconsistentTableError in places where the exception is related to parsing a table which is inconsistent with the specified table format. Note that InconsistentTableError inherits from ValueError so no user code changes are required. [#7425]

astropy.io.fits

• The fits.table_to_hdu() function will translate any column format attributes to a TDISPn format string, if possible, and store it as a TDISPn keyword in the HDU header. [#7226]

astropy.modeling

• Change the order of the return values from FittingWithOutlierRemoval, such that fitted_model comes first, for consistency with other fitters. For the second value, return only a boolean outlier mask, instead of the previous MaskedArray (which included a copy of the input data that was both redundant and inadvertently corrupted at masked points). Return a consistent type for the second value when niter=0. [#7407]

• Set the minimum value for the bolometric_flux parameter of the BlackBody1D model to zero. [#7045]

astropy.nddata

• Add two new uncertainty classes, astropy.nddata.VarianceUncertainty and astropy.nddata.InverseVariance. [#6971]

astropy.stats

• String values can now be used for the cenfunc and stdfunc keywords in the SigmaClip class and sigma_clip and sigma_clipped_stats functions. [#7478]

• The SigmaClip class and sigma_clip and sigma_clipped_stats functions now have a masked keyword, which can be used to return either a masked array (default) or an ndarray with the min/max values. [#7478]

• The iters keyword has been renamed (and deprecated) to maxiters in the SigmaClip class and sigma_clip and sigma_clipped_stats functions. [#7478]

astropy.table

• Table.read() on a FITS binary table file will convert any TDISPn header keywords to a Python formatting string when possible, and store it in the column format attribute. [#7226]

• No values provided to stack will now raise ValueError rather than TypeError. [#7674]

astropy.tests

• from astropy.tests.helper import * no longer includes quantity_allclose. However, from astropy.tests.helper import quantity_allclose would still work. [#7381]

• warnings_to_ignore_by_pyver option in enable_deprecations_as_exceptions() now takes None as key. Any deprecation message that is mapped to None will be ignored regardless of the Python version. [#7790]

astropy.time

• Added the ability to use local as time scale in Time and TimeDelta. [#6487]

• Comparisons, addition, and subtraction of Time instances with non-time instances will now return NotImplemented rather than raise the Time-specific OperandTypeError. This will generally lead to a regular TypeError. As a result, OperandTypeError now only occurs if the operation is between Time instances of incompatible type or scale. [#7584]

astropy.units

• In UnitBase.compose(), if a sequence (list|tuple) is passed in to units, the default for include_prefix_units is set to True, so that no units get ignored. [#6957]

• Negative parallaxes are now converted to NaN values when using the parallax equivalency. [#7988]

astropy.utils

• InheritDocstrings now also works on class properties. [#7166]

• diff_values(), report_diff_values(), and where_not_allclose() utility functions are moved from astropy.io.fits.diff. [#7444]

• invalidate_caches() has been removed from the astropy.utils.compat namespace, use it directly from importlib. [#7872]

astropy.visualization

• In ImageNormalize, the default for clip is set to True. [#7800]

• Changed AsymmetricPercentileInterval and MinMaxInterval to ignore NaN values in arrays. [#7360]

• Automatically default to using grid_type='contours' in WCSAxes when using a custom Transform object if the transform has no inverse. [#7847]

Performance Improvements

• Reduced import time by more cautious use of the standard library. [#7647]

astropy.convolution

• Major performance overhaul to convolve(). [#7293]

• convolve(): Boundaries fill, extend, and wrap now use a single implementation that pads the image with the correct boundary values before convolving. The runtimes of these three were significantly skewed. They now have equivalent runtimes that are also faster than before due to performant contiguous memory access. However, this does increase the memory footprint as an entire new image array is required plus that needed for the padded region.[#7293]

• convolve(): Core computation ported from Cython to C. Several optimization techniques have been implemented to achieve performance gains, e.g. compiler hoisting, and vectorization, etc. Compiler optimization level -O2 required for hoisting and -O3 for vectorization. [#7293]

• convolve(): nan_treatment=‘interpolate’ was slow to compute irrespective of whether any NaN values exist within the array. The input array is now checked for NaN values and interpolation is disabled if non are found. This is a significant performance boost for arrays without NaN values. [#7293]

astropy.coordinates

• Sped up creating SkyCoord objects by a factor of ~2 in some cases. [#7615]

• Sped up getting xyz vectors from CartesianRepresentation (which is used a lot internally). [#7638]

• Sped up transformations and some representation methods by replacing python code with (compiled) erfa ufuncs. [#7639]

• Sped up adding differential (velocity) data to representations by a factor of ~20, which improves the speed of frame and SkyCoord initialization. [#7924]

• Refactored SkyCoord initializer to improve performance and code clarity. [#7958]

• Sped up initialization of Longitude by ~40%. [#7616]

astropy.stats

• The SigmaClip class and sigma_clip and sigma_clipped_stats functions are now significantly faster. [#7478]

• A Cython implementation for astropy.stats.kuiper_two and a vectorized implementation for astropy.stats.kuiper_false_positive_probability have been added, speeding up both functions. [#8104]

astropy.units

• Sped up creating new composite units, and raising units to some power [#7549, #7649]

• Sped up Unit.to when target unit is the same as the original unit. [#7643]

• Lazy-load scipy.special to shorten astropy.units import time. [#7636]

astropy.visualization

• Significantly sped up drawing of contours in WCSAxes. [#7568]

Bug Fixes

astropy.convolution

• Fixed bug in convolve_fft where masked input was copied with numpy.asarray instead of numpy.asanyarray. numpy.asarray removes the mask subclass causing numpy.ma.ismasked(input) to fail, causing convolve_fft to ignore all masked input. [#8137]

• Remove function side-effects of input data from convolve_fft. It was possible for input data to remain modified if particular exceptions were raised. [#8152]

astropy.coordinates

• EarthLocation.of_address now uses the OpenStreetMap geocoding API by default to retrieve coordinates, with the Google API (which now requires an API key) as an option. [#7918]

• Fixed a bug that caused frame objects with NaN distances to have NaN sky positions, even if valid sky coordinates were specified. [#7988]

• Fixed represent_as() to not round-trip through cartesian if the same representation class as the instance is passed in. [#7988]

astropy.io.ascii

• Fixed a problem when guess=True that fast_reader options could be dropped after the first fast reader class was tried. [#5578]

• Units in CDS-formatted tables are now parsed correctly by the units module. [#7348]

astropy.io.misc

• Fixed bug when writing a table with masked columns to HDF5. Previously the mask was being silently dropped. If the serialize_meta option is enabled the data mask will now be written as an additional column and the masked columns will round-trip correctly. [#7481]

• Fixed a bug where writing to HDF5 failed for for tables with columns of unicode strings. Now those columns are first encoded to UTF-8 and written as byte strings. [#7024, #8017]

• Fixed a bug with serializing the bounding_box of models initialized with Quantities . [#8052]

astropy.io.fits

• Added support for copy.copy and copy.deepcopy for HDUList. [#7218]

• Override HDUList.copy() to return a shallow HDUList instance. [#7218]

astropy.modeling

• Fix behaviour of certain models with units, by making certain unit-related attributes readonly. [#7210]

• Fixed an issue with validating a bounding_box whose items are Quantities. [#8052]

• Fix Moffat1D and Moffat2D derivatives. [#8108]

astropy.nddata

• Fixed rounding behavior in overlap_slices for even-sized small arrays. [#7859]

• Added support for pickling NDData instances that have an uncertainty. [#7383]

astropy.stats

• Fix errors in kuiper_false_positive_probability. [#7975]

astropy.tests

• Fixing bug that prevented to run the doctests on only a single rst documentation file rather than all of them. [#8055]

astropy.time

• Fix a bug when setting a TimeDelta array item with plain float value(s). This was always interpreted as a JD (day) value regardless of the TimeDelta format. [#7990]

astropy.units

• To simplify fast creation of Quantity instances from arrays, one can now write array << unit (equivalent to Quantity(array, unit, copy=False)). If array is already a Quantity, this will convert the quantity to the requested units; in-place conversion can be done with quantity <<= unit. [#7734]

astropy.utils

• Fixed a bug due to which report_diff_values() was reporting incorrect number of differences when comparing two numpy.ndarray. [#7470]

• The download progress bar is now only displayed in terminals, to avoid polluting piped output. [#7577]

• Ignore URL mirror caching when there is no internet. [#8163]

astropy.visualization

• Right ascension coordinates are now shown in hours by default, and the set_format_unit method on CoordinateHelper now works correctly with angle coordinates. [#7215]

Other Changes and Additions

• The documentation build now uses the Sphinx configuration from sphinx-astropy rather than from astropy-helpers. [#7139]

• Versions of Numpy <1.13 are no longer supported. [#7058]

• Running tests now suppresses the output of the installation stage by default, to allow easier viewing of the test results. To re-enable the output as before, use python setup.py test --verbose-install. [#7512]

• The ERFA functions are now wrapped in ufuncs instead of custom C code, leading to some speed improvements, and setting the stage for allowing overrides with __array_ufunc__. [#7502]

• Updated the bundled CFITSIO library to 3.450. See cextern/cfitsio/docs/changes.txt for additional information. [#8014]

• The representation keywords in coordinate frames are now deprecated in favor of the representation_type keywords (which are less ambiguously named). [#8119]

Version 3.0.5 (2018-10-14)

Bug Fixes

astropy.coordinates

• Fixed bug in which consecutive StaticMatrixTransform’s in a frame transform path would be combined in the incorrect order. [#7707]

astropy.tests

• Fixing bug that doctests were not picked up from the narrative documentation when tests were run for all modules. [#7767]

Version 3.0.4 (2018-08-02)

API Changes

astropy.table

• The private _parent attribute in the info attribute of table columns was changed from a direct reference to the parent column to a weak reference. This was in response to a memory leak caused by having a circular reference cycle. This change means that expressions like col[3:5].info will now fail because at the point of the info property being evaluated the col[3:5] weak reference is dead. Instead force a reference with c = col[3:5] followed by c.info.indices. [#6277, #7448]

Bug Fixes

astropy.nddata

• Fixed an bug when creating the WCS of a cutout (see nddata.Cutout2D) when input image’s WCS contains SIP distortion corrections by adjusting the crpix of the astropy.wcs.Sip (in addition to adjusting the crpix of the astropy.wcs.WCS object). This bug had the potential to produce large errors in WCS coordinate transformations depending on the position of the cutout relative to the input image’s crpix. [#7556, #7550]

astropy.table

• Fix memory leak where updating a table column or deleting a table object was not releasing the memory due to a reference cycle in the column info attributes. [#6277, #7448]

astropy.wcs

• Fixed an bug when creating the WCS slice (see WCS.slice()) when WCS contains SIP distortion corrections by adjusting the WCS.sip.crpix in addition to adjusting WCS.wcs.crpix. This bug had the potential to produce large errors in WCS coordinate transformations depending on the position of the slice relative to WCS.wcs.crpix. [#7556, #7550]

Other Changes and Additions

• Updated bundled wcslib to v 5.19.1 [#7688]

Version 3.0.3 (2018-06-01)

Bug Fixes

astropy.io.ascii

• Fix stripping correct (header) comment line from meta['comments'] in the CommentedHeader reader for all header_start settings. [#7508]

astropy.io.fits

• Raise error when attempting to open gzipped FITS file in ‘append’ mode. [#7473]

• Fix a bug when writing to FITS a table that has a column description with embedded blank lines. [#7482]

astropy.tests

• Enabling running tests for multiple packages when specified comma separated. [#7463]

Version 3.0.2 (2018-04-23)

Bug Fixes

astropy.coordinates

• Computing a 3D separation between two SkyCoord objects (with the separation_3d method) now works with or without velocity data attached to the objects. [#7387]

astropy.io.votable

• Fix validate with xmllint=True. [#7255, #7283]

astropy.modeling

• FittingWithOutlierRemoval now handles model sets, as long as the underlying fitter supports masked values. [#7199]

• Remove assumption that model_set_axis == 0 for 2D models in LinearLSQFitter. [#7317, #7199]

• Fix the shape of the outputs when a model set is evaluated with model_set_axis=False . [#7317]

astropy.stats

• Accept a tuple for the axis parameter in sigma_clip, like the underlying numpy functions and some other functions in stats. [#7199]

astropy.tests

• The function quantity_allclose was moved to the units package with the new, shorter name allclose. This eliminates a runtime dependency on pytest which was causing issues for some affiliated packages. The old import will continue to work but may be deprecated in the future. [#7252]

astropy.units

• Added a units-aware allclose function (this was previously available in the tests module as quantity_allclose). To complement allclose, a new isclose function is also added and backported. [#7252]

Version 3.0.1 (2018-03-12)

Bug Fixes

astropy.io.ascii

• Fix a unicode decode error when reading a table with non-ASCII characters. The fast C reader cannot handle unicode so the code now uses the pure-Python reader in this case. [#7103]

astropy.io.fits

• Updated the bundled CFITSIO library to 3.430. This is to remedy a critical security vulnerability that was identified by NASA. See cextern/cfitsio/docs/changes.txt for additional information. [#7274]

astropy.io.misc

• Make sure that a sufficiently recent version of ASDF is installed when running test suite against ASDF tags and schemas. [#7205]

astropy.io.registry

• Fix reading files with serialized metadata when using a Table subclass. [#7213]

astropy.io.votable

• Fix lookup fields by ID. [#7208]

astropy.modeling

• Fix model set evaluation over common input when model_set_axis > 0. [#7222]

• Fixed the evaluation of compound models with units. This required adding the ability to have input_units_strict and input_units_allow_dimensionless be dictionaries with input names as keys. [#6952]

astropy.units

• quantity_helper no longer requires scipy>=0.18. [#7219]

Version 3.0 (2018-02-12)

New Features

astropy.constants

• New context manager set_enabled_constants to temporarily use an older version. [#7008]

astropy.coordinates

• The Distance object now accepts parallax as a keyword in the initializer, and supports retrieving a parallax (as an Angle) via the .parallax attributes. [#6855]

• The coordinate frame classes (subclasses of BaseCoordinateFrame) now always have .velocity, .proper_motion, and .radial_velocity properties that provide shorthands to the full-space Cartesian velocity as a CartesianDifferential, the 2D proper motion as a Quantity, and the radial or line-of-sight velocity as a Quantity. [#6869]

• SkyCoord objects now support storing and transforming differentials - i.e., both radial velocities and proper motions. [#6944]

• All frame classes now automatically get sensible representation mappings for velocity components. For example, d_x, d_y, d_z are all automatically mapped to frame component namse v_x, v_y, v_z. [#6856]

• SkyCoord objects now support updating the position of a source given its space motion and a new time or time difference. [#6872]

• The frame classes now accept a representation class or differential class, or string names for either, through the keyword arguments representation_type and differential_type instead of representation and differential_cls. [#6873]

• The frame classes (and SkyCoord) now give more useful error messages when incorrect attribute names are given. Instead of using the representation attribute names, they use the frame attribute names. [#7106]

• EarthLocation now has a method to compute the gravitational redshift due due to solar system bodies. [#6861, #6935]

• EarthLocation now has a get_gcrs convenience method to get the location in GCRS coordinates. [#6861, #6935]

astropy.io.fits

• Expanded the FITS Column interface to accept attributes pertaining to the FITS World Coordinate System, which includes spatial(celestial) and time coordinates. [#6359]

• Added ver attribute to set the EXTVER header keyword to ImageHDU and TableHDU. [#6454]

• The performance for reading FITS tables has been significantly improved, in particular for cases where the tables contain one or more string columns and when done through Table.read. [#6821]

• The performance for writing tables from Table.write has now been significantly improved for tables containing one or more string columns. [#6920]

• The Table.read now supports a memmap= keyword argument to control whether or not to use memory mapping when reading the table. [#6821]

• When reading FITS tables with fits.open, a new keyword argument character_as_bytes can be passed - when set to True, character columns are returned as Numpy byte arrays (Numpy type S) while when set to False, the same columns are decoded to Unicode strings (Numpy type U) which uses more memory. [#6821]

• The table_to_hdu function and the BinTableHDU.from_columns and FITS_rec.from_columns methods now include a character_as_bytes keyword argument - if set to True, then when string columns are accessed, byte columns will be returned, which can provide significantly improved performance. [#6920]

• Added support for writing and reading back a table which has “mixin columns” such as SkyCoord or EarthLocation with no loss of information. [#6912]

• Enable tab-completion for FITS_rec column names and Header keywords with IPython 5 and later. [#7071]

astropy.io.misc

• When writing to HDF5 files, the serialized metadata are now saved in a new dataset, instead of the HDF5 dataset attributes. This allows for metadata of any dimensions. [#6304]

• Added support in HDF5 for writing and reading back a table which has “mixin columns” such as SkyCoord or EarthLocation with no loss of information. [#7007]

• Add implementations of astropy-specific ASDF tag types. [#6790]

• Add ASDF tag and schema for ICRSCoord. [#6904]

astropy.modeling

• Add unit support for tabular models. [#6529]

• A deepcopy() method was added to models. [#6515]

• Added units support to AffineTransformation. [#6853]

• Added is_separable function to modeling to test the separability of a model. [#6746]

• Added Model.separable property. It returns a boolean value or None if not set. [#6746]

• Support masked array values in LinearLSQFitter (instead of silently ignoring the mask). [#6927]

astropy.stats

• Added false alarm probability computation to astropy.stats.LombScargle [#6488]

• Implemented Kuiper functions in astropy.stats [#3724, #6565]

astropy.table

• Added support for reading and writing astropy.time.Time Table columns to and from FITS tables, to the extent supported by the FITS standard. [#6176]

• Improved exception handling and error messages when column format attribute is incorrect for the column type. [#6385]

• Allow to pass htmldict option to the jsviewer writer. [#6551]

• Added new table operation astropy.table.setdiff that returns the set difference of table rows for two tables. [#6443]

• Added support for reading time columns in FITS compliant binary tables as astropy.time.Time Table columns. [#6442]

• Allowed to remove table rows through the __delitem__ method. [#5839]

• Added a new showtable command-line script to view binary or ASCII table files. [#6859]

• Added new table property astropy.table.Table.loc_indices that returns the location of rows by indexes. [#6831]

• Allow updating of table by indices through the property astropy.table.Table.loc. [#6831]

• Enable tab-completion for column names with IPython 5 and later. [#7071]

• Allow getting and setting a table Row using multiple column names. [#7107]

astropy.tests

• Split pytest plugins into separate modules. Move remotedata, openfiles, doctestplus plugins to standalone repositories. [#6384, #6606]

• When testing, astropy (or the package being tested) is now installed to a temporary directory instead of copying the build. This allows entry points to work correctly. [#6890]

• The tests_require setting in setup.py now works properly when running ‘python setup.py test’. [#6892]

astropy.units

• Deprecated conversion of quantities to truth values. Currently, the expression bool(0 * u.dimensionless_unscaled) evaluates to True. In the future, attempting to convert a Quantity to a bool will raise ValueError. [#6580, #6590]

• Modify the brightness_temperature equivalency to provide a surface brightness equivalency instead of the awkward assumed-per-beam equivalency that previously existed [#5173, #6663]

• Support was added for a number of scipy.special functions. [#6852]

astropy.utils

• The astropy.utils.console.ProgressBar.map class method now supports the ipython_widget option. You can now pass it both multiprocess=True and ipython_widget=True to get both multiprocess speedup and a progress bar widget in an IPython Notebook. [#6368]

• The astropy.utils.compat.funcsigs module has now been deprecated. Use the Python ‘inspect’ module directly instead. [#6598]

• The astropy.utils.compat.futures module has now been deprecated. Use the Python ‘concurrent.futures’ module directly instead. [#6598]

• JsonCustomEncoder is expanded to handle Quantity and UnitBase. [#5471]

• Added a dcip_xy method to IERS that interpolates along the dX_2000A and dY_2000A columns of the IERS table. Hence, the data for the CIP offsets is now available for use in coordinate frame conversion. [#5837]

• The functions matmul, broadcast_arrays, broadcast_to of the astropy.utils.compat.numpy module have been deprecated. Use the NumPy functions directly. [#6691]

• The astropy.utils.console.ProgressBar.map class method now returns results in sequential order. Previously, if you set multiprocess=True, then the results could arrive in any arbitrary order, which could be a nasty shock. Although the function will still be evaluated on the items in arbitrary order, the return values will arrive in the same order in which the input items were provided. The method is now a thin wrapper around astropy.utils.console.ProgressBar.map_unordered, which preserves the old behavior. [#6439]

astropy.visualization

• Enable Matplotlib’s subtraction shorthand syntax for composing and inverting transformations for the WCSWorld2PixelTransform and WCSPixel2WorldTransform classes by setting has_inverse to True. In order to implement a unit test, also implement the equality comparison operator for both classes. [#6531]

• Added automatic hiding of axes labels when no tick labels are drawn on that axis. This parameter can be configured with WCSAxes.coords[*].set_axislabel_visibility_rule so that labels are automatically hidden when no ticks are drawn or always shown. [#6774]

astropy.wcs

• Added a new function celestial_frame_to_wcs to convert from coordinate frames to WCS (the opposite of what wcs_to_celestial_frame currently does. [#6481]

• wcslib was updated to v 5.18. [#7066]

API Changes

astropy.convolution

• Gaussian2DKernel now accepts x_stddev in place of stddev with an option for y_stddev, if different. It also accepts theta like Gaussian2D model. [#3605, #6748]

astropy.coordinates

• Deprecated recommended_units for representations. These were used to ensure that any angle was presented in degrees in sky coordinates and frames. This is more logically done in the frame itself. [#6858]

• As noted above, the frame class attributes representation and differential_cls are being replaced by representation_type and differential_type. In the next version, using representation will raise a deprecation warning. [#6873]

• Coordinate frame classes now can’t be added to the frame transform graph if they have frame attribute names that conflict with any component names. This is so SkyCoord can uniquely identify and distinguish frame attributes from frame components. [#6871]

• Slicing and reshaping of SkyCoord and coordinate frames no longer passes the new object through __init__, but directly sets attributes on a new instance. This speeds up those methods by an order of magnitude, but means that any customization done in __init__ is by-passed. [#6941]

astropy.io.ascii

• Allow ECSV files to be auto-identified by Table.read or Table.write based on the .ecsv file name suffix. In this case it is not required to provide the format keyword. [#6552]

astropy.io.fits

• Automatically detect and handle compression in FITS files that are opened by passing a file handle to fits.open [#6373]

• Remove the nonstandard checksum option. [#6571]

astropy.io.misc

• When writing to HDF5 files, the serialized metadata are now saved in a new dataset instead of the HDF5 dataset attributes. This allows for metadata of any dimensions. [#6304]

• Deprecated the usecPickle kwarg of fnunpickle and fnpickle as it was needed only for Python2 usage. [#6655]

astropy.io.votable

• Add handling of tree.Group elements to tree.Resource. Unified I/O or conversion to astropy tables is not affected. [#6262]

astropy.modeling

• Removed deprecated GaussianAbsorption1D model. Use Const1D - Gaussian1D instead. [#6542]

• Removed the registry from modeling. [#6706]

astropy.table

• When setting the column format attribute the value is now immediately validated. Previously one could set to any value and it was only checked when actually formatting the column. [#6385]

• Deprecated the python3_only kwarg of the convert_bytestring_to_unicode and convert_unicode_to_bytestring methods it was needed only for Python2 usage. [#6655]

• When reading in FITS tables with Table.read, string columns are now represented using Numpy byte (dtype S) arrays rather than Numpy unicode arrays (dtype U). The Column class then ensures the bytes are automatically converted to string as needed. [#6821]

• When getting a table row using multiple column names, if one of the names is not a valid column name then a KeyError exception is now raised (previously ValueError). When setting a table row, if the right hand side is not a sequence with the correct length then a ValueError is now raised (previously in certain cases a TypeError was raised). [#7107]

astropy.utils

• download_files_in_parallel now always uses cache=True to make the function work on Windows. [#6671]

astropy.visualization

• The Astropy matplotlib plot style has been deprecated. It will continue to work in future but is no longer documented. [#6991]

Bug Fixes

astropy.coordinates

• Frame objects now use the default differential even if the representation is explicitly provided as long as the representation provided is the same type as the default representation. [#6944]

• Coordinate frame classes now raise an error when they are added to the frame transform graph if they have frame attribute names that conflict with any component names. [#6871]

astropy.io.ascii

• Added support for reading very large tables in chunks to reduce memory usage. [#6458]

• Strip leading/trailing white-space from latex lines to avoid issues when matching \begin{tabular} statements. This is done by introducing a new LatexInputter class to override the BaseInputter. [#6311]

astropy.io.fits

• Properly handle opening of FITS files from http.client.HTTPResponse (i.e. it now works correctly when passing the results of urllib.request.urlopen to fits.open). [#6378]

• Fix the fitscheck script for updating invalid checksums, or removing checksums. [#6571]

• Fixed potential problems with the compression module [#6732]

• Always use the ‘D’ format for floating point values in ascii tables. [#6938]

astropy.table

• Fix getting a table row when using multiple column names (for example t[3]['a', 'b', 'c']). Also fix a problem when setting an entire row: if setting one of the right-hand side values failed this could result in a partial update of the referenced parent table before the exception is raised. [#7107]

astropy.time

• Initialization of Time instances with bytes or arrays with dtype S will now automatically attempt to decode as ASCII. This ensures Column instances with ASCII strings stored with dtype S can be used. [#6823, #6903]

astropy.units

• Fixed a bug that caused PLY files to not be generated correctly in Python 3. [#7174]

astropy.utils

• The deprecated decorator applied to a class will now modify the class itself, rather than to create a class that just looks and behave like the original. This is needed so that the Python 3 super without arguments works for decorated classes. [#6615]

• Fixed HomogeneousList when setting one item or a slice. [#6773]

• Also check the type when creating a new instance of HomogeneousList. [#6773]

• Make HomogeneousList work with iterators and generators when creating the instance, extending it, or using when setting a slice. [#6773]

Other Changes and Additions

• Versions of Python <3.5 are no longer supported. [#6556]

• Versions of Pytest <3.1 are no longer supported. [#6419]

• Versions of Numpy <1.10 are no longer supported. [#6593]

• The bundled CFITSIO was updated to version 3.41 [#6477]

• analytic_functions sub-package is removed. Use astropy.modeling.blackbody. [#6541]

• astropy.vo sub-package is removed. Use astropy.samp for SAMP and astroquery for VO cone search. [#6540]

• The guide to setting up Emacs for code development was simplified, and updated to recommend flycheck and flake8 for syntax checks. [#6692]

• The bundled version of PLY was updated to 3.10. [#7174]

Version 2.0.16 (2019-10-27)

Bug Fixes

astropy.time

• Fixed a troubling bug in which Time could loose precision, with deviations of 300 ns. [#9328]

Other Changes and Additions

• Updated IERS A URLs due to USNO prolonged maintenance. [#9443]

Version 2.0.15 (2019-10-06)

Bug Fixes

astropy.coordinates

• Fixed a bug where the string representation of a BaseCoordinateFrame object could become garbled under specific circumstances when the frame defines custom component names via RepresentationMapping. [#8869]

astropy.io.fits

• Fix uint conversion in FITS_rec when slicing a table. [#8982]

• Fix reading of unsigned 8-bit integer with compressed fits. [#9219]

astropy.nddata

• Fixed a bug in overlap_slices where the "strict" mode was too strict for a small array along the upper edge of the large array. [#8901]

• Fixed a bug in overlap_slices where a NoOverlapError would be incorrectly raised for a 0-shaped small array at the origin. [#8901]

astropy.samp

• Fixed a bug that caused an incorrectly constructed warning message to raise an error. [#8966]

astropy.table

• Fix FixedWidthNoHeader to pay attention to data_start keyword when finding first data line to split columns [#8485, #8511]

• Fix bug when initializing Table with rows as a generator. [#9315]

• Fix join when there are multiple mixin (Quantity) columns as keys. [#9313]

astropy.units

• Quantity now preserves the dtype for anything that is floating point, including float16. [#8872]

• Unit() now accepts units with fractional exponents such as m(3/2) in the default/fits and vounit formats that would previously have been rejected for containing multiple solidi (/). [#9000]

• Fixed the LaTeX representation of units containing a superscript. [#9218]

astropy.visualization

• Fixed compatibility issues with latest versions of Matplotlib. [#8961]

Other Changes and Additions

• Updated required version of Cython to v0.29.13 to make sure that generated C files are compatible with the upcoming Python 3.8 release as well as earlier supported versions of Python. [#9198]

Version 2.0.14 (2019-06-14)

Bug Fixes

astropy.io.fits

• Fix Header.update which was dropping the comments when passed a Header object. [#8840]

astropy.modeling

• Moffat1D.fwhm and Moffat2D.fwhm will return a positive value when gamma is negative. [#8801, #8815]

astropy.units

• Fixed a bug that prevented EarthLocation from being initialized with numpy >=1.17. [#8849]

astropy.visualization

• Fixed quantity_support to work around the fact that matplotlib does not detect subclasses in its units framework. With this, Angle and other subclasses work correctly. [#8818]

• Fixed quantity_support to work properly if multiple context managers are nested. [#8844]

Version 2.0.13 (2019-06-08)

Bug Fixes

astropy.io.fits

• Fixed bug in ColDefs._init_from_array() that caused unsigned datatypes with the opposite endianness as the host architecture to fail the TestColumnFunctions.test_coldefs_init_from_array unit test. [#8460]

astropy.io.misc

• Explicitly set PyYAML default flow style to None to ensure consistent astropy YAML output for PyYAML version 5.1 and later. [#8500]

astropy.io.votable

• Block floating-point columns from using repr format when converted to Table [#8358]

astropy.stats

• Fixed issue in bayesian_blocks when called with the ncp_prior keyword. [#8339]

astropy.units

• Fix take when one gets only a single element from a Quantity, ensuring it returns a Quantity rather than a scalar. [#8617]

Version 2.0.12 (2019-02-23)

New Features

astropy.utils

• The deprecated_renamed_argument decorator now capable deprecating an argument without renaming it. It also got a new alternative keyword argument to suggest alternative functionality instead of the removed one. [#8324]

Bug Fixes

astropy.io.fits

• Fixed bug in ColDefs._init_from_array() that caused non-scalar unsigned entries to not have the correct bzero value set. [#8353]

astropy.modeling

• Fixed compatibility of JointFitter with the latest version of Numpy. [#7984]

astropy.table

• Fix .quantity property of Column class for function-units (e.g., dex). Previously setting this was possible, but getting raised an error. [#8425]

• Fixes a bug where initializing a new Table from the final row of an existing Table failed. This happened when that row was generated using the item index [-1]. [#8422]

astropy.wcs

• Fix bug that caused WCS.has_celestial, wcs_to_celestial_frame, and other functionality depending on it to fail in the presence of correlated celestial and other axes. [#8420]

Other Changes and Additions

• Fixed make clean for the documentation on Windows to ensure it properly removes the api and generated directories. [#8346]

• Updating bundled pytest-openfiles to v0.3.2. [#8434]

• Making ErfaWarning and ErfaError available via astropy.utils.exceptions. [#8441]

Version 2.0.11 (2018-12-31)

Bug Fixes

astropy.io.ascii

• Fix fast reader C tokenizer to handle double quotes in quoted field. [#8283]

astropy.io.fits

• Fix a bug in io.fits with writing Fortran-ordered arrays to file objects. [#8282]

astropy.units

• Add support for np.matmul as a ufunc (new in numpy 1.16). [#8264, #8305]

astropy.utils

• Fix failures caused by IERS_A_URL being unavailable by introducing IERS_A_URL_MIRROR. [#8308]

Version 2.0.10 (2018-12-04)

Bug Fixes

astropy.convolution

• Fix Moffat2DKernel’s FWHM computation, which has an influence on the default size of the kernel when no size is given. [#8105]

astropy.coordinates

• Disable of_address usage due to Google API now requiring API key. [#7993]

astropy.io.fits

• fits.append now correctly handles file objects with valid modes other than ostream. [#7856]

astropy.table

• Fix Table.show_in_notebook failure when mixin columns are present. [#8069]

astropy.tests

• Explicitly disallow incompatible versions of pytest when using the test runner. [#8188]

astropy.units

• Fixed the spelling of the ‘luminous emittance/illuminance’ physical property. [#7942]

astropy.visualization

• Fixed a bug that caused origin to be incorrect if not specified. [#7927]

• Fixed a bug that caused an error when plotting grids multiple times with grid_type=’contours’. [#7927]

• Put an upper limit on the number of bins in hist and histogram and factor out calculation of bin edges into public function calculate_bin_edges. [#7991]

Other Changes and Additions

• Fixing astropy.__citation__ to provide the full bibtex entry of the 2018 paper. [#8110]

• Pytest 4.0 is not supported by the 2.0.x LTS releases. [#8173]

• Updating bundled pytest-remotedata to v0.3.1. [#8174]

• Updating bundled pytest-doctestplus to v0.2.0. [#8175]

• Updating bundled pytest-openfiles to v0.3.0. [#8176]

• Adding warning_type keyword argument to the “deprecated” decorators to allow issuing custom warning types instead of the default AstropyDeprecationWarning. [#8178]

Version 2.0.9 (2018-10-14)

Bug Fixes

astropy.io.ascii

• Fix reading of big files with the fast reader. [#7885]

astropy.io.fits

• HDUList.__contains__() now works with HDU arguments. That is, hdulist[0] in hdulist now works as expected. [#7282]

• HDUList s can now be written to streams in Python 3 [#7850]

astropy.nddata

• Fixed the bug in CCData.read when the HDU is not specified and the first one is empty so the function searches for the first HDU with data which may not have an image extension. [#7739]

astropy.stats

• Fixed bugs in biweight statistics functions where a constant data array (or if using the axis keyword, constant along an axis) would return NaN. [#7737]

astropy.table

• Fixed a bug in to_pandas() where integer type masked columns were always getting converted to float. This could cause loss of precision. Now this only occurs if there are actually masked data values, in which case pandas does require the values to be float so that NaN can be used to mark the masked values. [#7741, #7747]

astropy.tests

• Change the name of the configuration variable controlling the location of the Astropy cache in the Pytest plugin from cache_dir to astropy_cache_dir. The command line flag also changed to --astropy-cache-dir. This prevents a conflict with the cache_dir variable provided by pytest itself. Also made similar change to config_dir option as a precaution. [#7721]

astropy.units

• UnrecognizedUnit instances can now be compared to any other object without raising TypeError. [#7606]

astropy.visualization

• Fix compatibility with Matplotlib 3.0. [#7839]

• Fix an issue that caused a crash when using WCSAxes with a custom Transform object and when using grid_type='contours' to plot a grid. [#7846]

astropy.wcs

• Instead of raising an error astropy.wcs now returns the input when the input has zero size. [#7746]

• Fix malloc(0) bug in pipeline_all_pixel2world() and pipeline_pix2foc(). They now raise an exception for input with zero coordinates, i.e. shape = (0, n). [#7806]

• Fixed an issue with scalar input when WCS.naxis is one. [#7858]

Other Changes and Additions

• Added a new astropy.__citation__ attribute which gives a citation for Astropy in bibtex format. Made sure that both this and astropy.__bibtex__ works outside the source environment, too. [#7718]

Version 2.0.8 (2018-08-02)

Bug Fixes

astropy.convolution

• Correct data type conversion for non-float masked kernels. [#7542]

• Fix non-float or masked, zero sum kernels when normalize_kernel=False. Non-floats would yield a type error and masked kernels were not being filled. [#7541]

astropy.coordinates

• Ensure that relative humidities can be given as Quantities, rather than take any quantity and just strip its unit. [#7668]

astropy.nddata

• Fixed Cutout2D output WCS NAXIS values to reflect the cutout image size. [#7552]

astropy.table

• Fixed a bug in add_columns method where rename_duplicate=True would cause an error if there were no duplicates. [#7540]

astropy.tests

• Fixed bug in python setup.py test --coverage on Windows machines. [#7673]

astropy.time

• Avoid rounding errors when converting Quantity to TimeDelta. [#7625]

astropy.visualization

• Fixed a bug that caused the position of the tick values in decimal mode to be incorrectly determined. [#7332]

astropy.wcs

• Fixed a bug that caused wcs_to_celestial_frame, skycoord_to_pixel, and pixel_to_skycoord to raise an error if the axes of the celestial WCS were swapped. [#7691]

Version 2.0.7 (2018-06-01)

Bug Fixes

astropy.modeling

• Fixed Tabular models to not change the shape of data. [#7411]

astropy.stats

• In freedman_bin_width, if the data has too small IQR, raise ValueError. [#7248, #7402]

astropy.table

• Fix a performance issue in MaskedColumn where initialization was extremely slow for large arrays with the default mask=None. [#7422]

• Fix printing table row indexed with unsigned integer. [#7469]

• Fix copy of mask when copying a Table, as this is no more done systematically by Numpy since version 1.14. Also fixed a problem when MaskedColumn was initialized with mask=np.ma.nomask. [#7486]

astropy.time

• Fixed a bug in Time that raised an error when initializing a subclass of Time with a Time object. [#7453]

astropy.utils

• Fixed a bug that improperly handled unicode case of URL mirror in Python 2. [#7493]

astropy.visualization

• Fixed a bug that prevented legends from being added to plots done with units. [#7510]

Other Changes and Additions

• Bundled pytest-remotedata plugin is upgraded to 0.3. [#7493]

Version 2.0.6 (2018-04-23)

Bug Fixes

astropy.convolution

• convolve(boundary=None) requires the kernel to be smaller than the image. This was never actually checked, it now is and an exception is raised. [#7313]

astropy.units

• u.quantity_input no longer errors if the return annotation for a function is None. [#7336, #7380]

astropy.visualization

• Explicitly default to origin=’lower’ in WCSAxes. [#7331]

• Lists of units are now converted in the Matplotlib unit converter. This means that for Matplotlib versions later than 2.2, more plotting functions now work with units (e.g. errorbar). [#7037]

Other Changes and Additions

• Updated the bundled CFITSIO library to 3.44. This is to remedy another critical security vulnerability that was identified by NASA. See cextern/cfitsio/docs/changes.txt for additional information. [#7370]

Version 2.0.5 (2018-03-12)

Bug Fixes

astropy.coordinates

• Add a workaround for a bug in the einsum function in Numpy 1.14.0. [#7187]

• Fix problems with printing Angle instances under numpy 1.14.1. [#7234]

astropy.io.fits

• Fixed the fitsdiff script for matching fits file with one in a directory path. [#7085]

• Make sure that lazily-loaded HDUList is automatically loaded when calling hdulist.pop. [#7186]

astropy.modeling

• Propagate weights to underlying fitter in FittingWithOutlierRemoval [#7249]

astropy.tests

• Support dotted package names as namespace packages when gathering test coverage. [#7170]

astropy.visualization

• Matplotlib axes have the axisbelow property to control the z-order of ticks, tick labels, and grid lines. WCSAxes will now respect this property. This is useful for drawing scale bars or inset boxes, which should have a z-order that places them above all ticks and gridlines. [#7098]

Other Changes and Additions

• Updated the bundled CFITSIO library to 3.430. This is to remedy a critical security vulnerability that was identified by NASA. See cextern/cfitsio/docs/changes.txt for additional information. [#7274, #7275]

Version 2.0.4 (2018-02-06)

Bug Fixes

astropy.convolution

• Fixed IndexError when preserve_nan=True in convolve_fft. Added testing with preserve_nan=True. [#7000]

astropy.coordinates

• The sites.json file is now parsed explicitly with a UTF-8 encoding. This means that future revisions to the file with unicode observatory names can be done without breaking the site registry parser. [#7082]

• Working around a bug in Numpy 1.14.0 that broke some coordinate transformations. [#7105]

• Fixed a bug where negative angles could be rounded wrongly when converting to a string with seconds omitted. [#7148]

astropy.io.fits

• When datafile is missing, fits.tabledump uses input file name to build output file name. Fixed how it gets input file name from HDUList. [#6976]

• Fix in-place updates to scaled columns. [#6956]

astropy.io.registry

• Fixed bug in identifying inherited registrations from multiple ancestors [#7156]

astropy.modeling

• Fixed a bug in LevMarLSQFitter when fitting 2D models with constraints. [#6705]

astropy.utils

• download_file function will check for cache downloaded from mirror URL first before attempting actual download if primary URL is unavailable. [#6987]

astropy.visualization

• Fixed test failures for astropy.visualization.wcsaxes which were due to local matplotlibrc files being taken into account. [#7132]

Other Changes and Additions

• Fixed broken links in the documentation. [#6745]

• Substantial performance improvement (potentially >1000x for some cases) when converting non-scalar coordinates.Angle objects to strings. [#7004]

Version 2.0.3 (2017-12-13)

Bug Fixes

astropy.coordinates

• Ecliptic frame classes now support attributes v_x, v_y, v_z when using with a Cartesian representation. [#6569]

• Added a nicer error message when accidentally calling frame.representation instead of frame.data in the context of methods that use ._apply(). [#6561]

• Creating a new SkyCoord from a list of multiple SkyCoord objects now yield the correct type of frame, and works at all for non-equatorial frames. [#6612]

• Improved accuracy of velocity calculation in EarthLocation.get_gcrs_posvel. [#6699]

• Improved accuracy of radial velocity corrections in SkyCoord.radial_velocity_correction`. [#6861]

• The precision of ecliptic frames is now much better, after removing the nutation from the rotation and fixing the computation of the position of the Sun. [#6508]

astropy.extern

• Version 0.2.1 of pytest-astropy is included as an external package. [#6918]

astropy.io.fits

• Fix writing the result of fitsdiff to file with --output-file. [#6621]

• Fix a minor bug where FITS_rec instances can not be indexed with tuples and other sequences that end up with a scalar. [#6955, #6966]

astropy.io.misc

• Fix ImportError when hdf5 is imported first in a fresh Python interpreter in Python 3. [#6604, #6610]

astropy.nddata

• Suppress errors during WCS creation in CCDData.read(). [#6500]

• Fixed a problem with CCDData.read when the extension wasn’t given and the primary HDU contained no data but another HDU did. In that case the header were not correctly combined. [#6489]

astropy.stats

• Fixed an issue where the biweight statistics functions would sometimes cause runtime underflow/overflow errors for float32 input arrays. [#6905]

astropy.table

• Fixed a problem when printing a table when a column is deleted and garbage-collected, and the format function caching mechanism happens to re-use the same cache key. [#6714]

• Fixed a problem when comparing a unicode masked column (on left side) to a bytes masked column (on right side). [#6899]

• Fixed a problem in comparing masked columns in bytes and unicode when the unicode had masked entries. [#6899]

astropy.tests

• Fixed a bug that causes tests for rst files to not be run on certain platforms. [#6555, #6608]

• Fixed a bug that caused the doctestplus plugin to not work nicely with the hypothesis package. [#6605, #6609]

• Fixed a bug that meant that the data.astropy.org mirror could not be used when using –remote-data=astropy. [#6724]

• Support compatibility with new pytest-astropy plugins. [#6918]

• When testing, astropy (or the package being tested) is now installed to a temporary directory instead of copying the build. This allows entry points to work correctly. [#6890]

astropy.time

• Initialization of Time instances now is consistent for all formats to ensure that -0.5 <= jd2 < 0.5. [#6653]

astropy.units

• Ensure that Quantity slices can be set with objects that have a unit attribute (such as Column). [#6123]

astropy.utils

• download_files_in_parallel now respects the given timeout value. [#6658]

• Fixed bugs in remote data handling and also in IERS unit test related to path URL, and URI normalization on Windows. [#6651]

• Fixed a bug that caused get_pkg_data_fileobj to not work correctly when used with non-local data from inside packages. [#6724]

• Make sure get_pkg_data_fileobj fails if the URL can not be read, and correctly falls back on the mirror if necessary. [#6767]

• Fix the finddiff option in find_current_module to properly deal with submodules. [#6767]

• Fixed pyreadline import in utils.console.isatty for older IPython versions on Windows. [#6800]

astropy.visualization

• Fixed the vertical orientation of the fits2bitmap output bitmap image to match that of the FITS image. [#6844, #6969]

• Added a workaround for a bug in matplotlib so that the fits2bitmap script generates the correct output file type. [#6969]

Other Changes and Additions

• No longer require LaTeX to build the documentation locally and use mathjax instead. [#6701]

• Ensured that all tests use the Astropy data mirror if needed. [#6767]

Version 2.0.2 (2017-09-08)

Bug Fixes

astropy.coordinates

• Ensure transformations via ICRS also work for coordinates that use cartesian representations. [#6440]

• Fixed a bug that was preventing SkyCoord objects made from lists of other coordinate objects from being written out to ECSV files. [#6448]

astropy.io.fits

• Support the GZIP_2 FITS image compression algorithm as claimed in docs. [#6486]

astropy.io.votable

• Fixed a bug that wrote out VO table as version 1.2 instead of 1.3. [#6521]

astropy.table

• Fix a bug when combining unicode columns via join or vstack. The character width of the output column was a factor of 4 larger than needed. [#6459]

astropy.tests

• Fixed running the test suite using –parallel. [#6415]

• Added error handling for attempting to run tests in parallel without having the pytest-xdist package installed. [#6416]

• Fixed issue running doctests with pytest>=3.2. [#6423, #6430]

• Fixed issue caused by antivirus software in response to malformed compressed files used for testing. [#6522]

• Updated top-level config file to properly ignore top-level directories. [#6449]

astropy.units

• Quantity._repr_latex_ now respects precision option from numpy printoptions. [#6412]

astropy.utils

• For the deprecated_renamed_argument decorator, refer to the deprecation‘s caller instead of astropy.utils.decorators, to makes it easier to find where the deprecation warnings comes from. [#6422]

Version 2.0.1 (2017-07-30)

Bug Fixes

astropy.constants

• Fixed Earth radius to be the IAU2015 value for the equatorial radius. The polar value had erroneously been used in 2.0. [#6400]

astropy.coordinates

• Added old frame attribute classes back to top-level namespace of astropy.coordinates. [#6357]

astropy.io.fits

• Scaling an image always uses user-supplied values when given. Added defaults for scaling when bscale/bzero are not present (float images). Fixed a small bug in when to reset _orig_bscale. [#5955]

astropy.modeling

• Fixed a bug in initializing compound models with units. [#6398]

astropy.nddata

• Updating CCDData.read() to be more flexible with inputs, don’t try to delete keywords that are missing from the header. [#6388]

astropy.tests

• Fixed the test command that is run from setuptools to allow it to gracefully handle keyboard interrupts and pass them on to the pytest subprocess. This prompts pytest to teardown and display useful traceback and test information [#6369]

astropy.visualization

• Ticks and tick labels are now drawn in front of, rather than behind, gridlines in WCS axes. This improves legibility in situations where tick labels may be on the interior of the axes frame, such as the right ascension axis of an all-sky Aitoff or Mollweide projection. [#6361]

astropy.wcs

• Fix the missing wcskey part in _read_sip_kw, this will cause error when reading sip wcs while there is no default CRPIX1 CRPIX2 keywords and only CRPIX1n CRPIX2n in header. [#6372]

Version 2.0 (2017-07-07)

New Features

astropy.constants

• Constants are now organized into version modules, with physical CODATA constants in the codata2010 and codata2014 sub-modules, and astronomical constants defined by the IAU in the iau2012 and iau2015 sub-modules. The default constants in astropy.constants in Astropy 2.0 have been updated from iau2012 to iau2015 and from codata2010 to codata2014. The constants for 1.3 can be accessed in the astropyconst13 sub-module and the constants for 2.0 (the default in astropy.constants) can also be accessed in the astropyconst20 sub-module [#6083]

• The GM mass parameters recommended by IAU 2015 Resolution B 3 have been added as GM_sun, GM_jup, and GM_earth, for the Sun, Jupiter and the Earth. [#6083]

astropy.convolution

• Major change in convolution behavior and keyword arguments. Additional details are in the API section. [#5782]

• Convolution with un-normalized and un-normalizable kernels is now possible. [#5782]

• Add a new argument, normalization_rtol, to convolve_fft, allowing the user to specify the relative error tolerance in the normalization of the convolution kernel. [#5649, #5177]

• Models can now be convoluted using convolve or convolve_fft, which generates a regular compound model. [#6015]

astropy.coordinates

• Frame attributes set on SkyCoord are now always validated, and any ndarray-like operation (like slicing) will also be done on those. [#5751]

• Caching of all possible frame attributes was implemented. This greatly speeds up many SkyCoord operations. [#5703, #5751]

• A class hierarchy was added to allow the representation layer to store differentials (i.e., finite derivatives) of coordinates. This is intended to enable support for velocities in coordinate frames. [#5871]

• replicate_without_data and replicate methods were added to coordinate frames that allow copying an existing frame object with various reference or copy behaviors and possibly overriding frame attributes. [#6182]

• The representation class instances can now contain differential objects. This is primarily useful for internal operations that will provide support for transforming velocity components in coordinate frames. [#6169]

• EarthLocation.to_geodetic() (and EarthLocation.geodetic) now return namedtuples instead of regular tuples. [#6237]

• EarthLocation now has lat and lon properties (equivalent to, but preferred over, the previous latitude and longitude). [#6237]

• Added a radial_velocity_correction method to SkyCoord to do compute barycentric and heliocentric velocity corrections. [#5752]

• Added a new AffineTransform class for coordinate frame transformations. This class supports matrix operations with vector offsets in position or any differential quantities (so far, only velocity is supported). The matrix transform classes now subclass from the base affine transform. [#6218]

• Frame objects now have experimental support for velocity components. Most frames default to accepting proper motion components and radial velocity, and the velocities transform correctly for any transformation that uses one of the AffineTransform-type transformations. For other transformations a finite-difference velocity transformation is available, although it is not as numerically stable as those that use AffineTransform-type transformations. [#6219, #6226]

astropy.io.ascii

• Allow to specify encoding in ascii.read, only for Python 3 and with the pure-Python readers. [#5448]

• Writing latex tables with only a tabular environment is now possible by setting latexdict['tabletyle'] to None. [#6205]

• Allow ECSV format to support reading and writing mixin columns like Time, SkyCoord, Latitude, and EarthLocation. [#6181]

astropy.io.fits

• Checking available disk space before writing out file. [#5550, #4065]

• Change behavior to warn about units that are not FITS-compliant when writing a FITS file but not when reading. [#5675]

• Added absolute tolerance parameter when comparing FITS files. [#4729]

• New convenience function printdiff to print out diff reports. [#5759]

• Allow to instantiate a BinTableHDU directly from a Table object. [#6139]

astropy.io.misc

• YAML representer now also accepts numpy types. [#6077]

astropy.io.registry

• New functions to unregister readers, writers, and identifiers. [#6217]

astropy.modeling

• Added SmoothlyBrokenPowerLaw1D model. [#5656]

• Add n_submodels shared method to single and compound models, which allows users to get the number of components of a given single (compound) model. [#5747]

• Added a name setter for instances of _CompoundModel. [#5741]

• Added FWHM properties to Gaussian and Moffat models. [#6027]

• Added support for evaluating models and setting the results for inputs outside the bounding_box to a user specified fill_value. This is controlled by a new optional boolean keyword with_bounding_box. [#6081]

• Added infrastructure support for units on parameters and during model evaluation and fitting, added support for units on all functional, power-law, polynomial, and rotation models where this is appropriate. A new BlackBody1D model has been added. [#4855, #6183, #6204, #6235]

astropy.nddata

• Added an image class, CCDData. [#6173]

astropy.stats

• Added biweight_midcovariance function. [#5777]

• Added biweight_scale and biweight_midcorrelation functions. [#5991]

• median_absolute_deviation and mad_std have ignore_nan option that will use np.ma.median with nans masked out or np.nanmedian instead of np.median when computing the median. [#5232]

• Implemented statistical estimators for Ripley’s K Function. [#5712]

• Added SigmaClip class. [#6206]

• Added std_ddof keyword option to sigma_clipped_stats. [#6066, #6207]

astropy.table

• Issue a warning when assigning a string value to a column and the string gets truncated. This can occur because numpy string arrays are fixed-width and silently drop characters which do not fit within the fixed width. [#5624, #5819]

• Added functionality to allow astropy.units.Quantity to be written as a normal column to FITS files. [#5910]

• Add support for Quantity columns (within a QTable) in table join(), hstack() and vstack() operations. [#5841]

• Allow unicode strings to be stored in a Table bytestring column in Python 3 using UTF-8 encoding. Allow comparison and assignment of Python 3 str object in a bytestring column (numpy 'S' dtype). If comparison with str instead of bytes is a problem (and bytes is really more logical), please open an issue on GitHub. [#5700]

• Added functionality to allow astropy.units.Quantity to be read from and written to a VOtable file. [#6132]

• Added support for reading and writing a table with mixin columns like Time, SkyCoord, Latitude, and EarthLocation via the ASCII ECSV format. [#6181]

• Bug fix for MaskedColumn insert method, where fill_value attribute was not being passed along to the copy of the MaskedColumn that was returned. [#7585]

astropy.tests

• enable_deprecations_as_exceptions function now accepts additional user-defined module imports and warning messages to ignore. [#6223, #6334]

astropy.units

• The astropy.units.quantity_input decorator will now convert the output to the unit specified as a return annotation under Python 3. [#5606]

• Passing a logarithmic unit to the Quantity constructor now returns the appropriate logarithmic quantity class if subok=True. For instance, Quantity(1, u.dex(u.m), subok=True) yields <Dex 1.0 dex(m)>. [#5928]

• The quantity_input decorator now accepts a string physical type in addition to of a unit object to specify the expected input Quantity’s physical type. For example, @u.quantity_input(x='angle') is now functionally the same as @u.quantity_input(x=u.degree). [#3847]

• The quantity_input decorator now also supports unit checking for optional keyword arguments and accepts iterables of units or physical types for specifying multiple valid equivalent inputs. For example, @u.quantity_input(x=['angle', 'angular speed']) or @u.quantity_input(x=[u.radian, u.radian/u.yr]) would both allow either a Quantity angle or angular speed passed in to the argument x. [#5653]

• Added a new equivalence molar_mass_amu between g/mol to atomic mass units. [#6040, #6113]

• Quantity has gained a new to_value method which returns the value of the quantity in a given unit. [#6127]

• Quantity now supports the @ operator for matrix multiplication that was introduced in Python 3.5, for all supported versions of numpy. [#6144]

• Quantity supports the new __array_ufunc__ protocol introduced in numpy 1.13. As a result, operations that involve unit conversion will be sped up considerably (by up to a factor of two for costly operations such as trigonometric ones). [#2583]

astropy.utils

• Added a new dataurl_mirror configuration item in astropy.utils.data that is used to indicate a mirror for the astropy data server. [#5547]

• Added a new convenience method get_cached_urls to astropy.utils.data for getting a list of the URLs in your cache. [#6242]

astropy.wcs

• Upgraded the included wcslib to version 5.16. [#6225]

  The minimum required version of wcslib in is 5.14.

API Changes

astropy.analytic_functions

• This entire sub-package is deprecated because blackbody has been moved to astropy.modeling.blackbody. [#6191]

astropy.convolution

• Major change in convolution behavior and keyword arguments. astropy.convolution.convolve_fft replaced interpolate_nan with nan_treatment, and astropy.convolution.convolve received a new nan_treatment argument. astropy.convolution.convolve also no longer double-interpolates interpolates over NaNs, although that is now available as a separate astropy.convolution.interpolate_replace_nans function. See the backwards compatibility note for more on how to get the old behavior (and why you probably don’t want to.) [#5782]

astropy.coordinates

• The astropy.coordinates.Galactic frame previously was had the cartesian ordering ‘w’, ‘u’, ‘v’ (for ‘x’, ‘y’, and ‘z’, respectively). This was an error and against the common convention. The ‘x’, ‘y’, and ‘z’ axes now map to ‘u’, ‘v’, and ‘w’, following the right-handed (‘u’ points to the Galactic center) convention. [#6330]

• Removed deprecated angles.rotation_matrix and angles.angle_axis. Use the routines in coordinates.matrix_utilities instead. [#6170]

• EarthLocation.latitude and EarthLocation.longitude are now deprecated in favor of EarthLocation.lat and EarthLocation.lon. They former will be removed in a future version. [#6237]

• The FrameAttribute class and subclasses have been renamed to just contain Attribute. For example, QuantityFrameAttribute is now QuantityAttribute. [#6300]

astropy.cosmology

• Cosmological models do not include any contribution from neutrinos or photons by default – that is, the default value of Tcmb0 is 0. This does not affect built in models (such as WMAP or Planck). [#6112]

astropy.io.fits

• Remove deprecated NumCode and ImgCode properties on FITS _ImageBaseHDU. Use module-level constants BITPIX2DTYPE and DTYPE2BITPIX instead. [#4993]

• comments meta key (which is io.ascii’s table convention) is output to COMMENT instead of COMMENTS header. Similarly, COMMENT headers are read into comments meta [#6097]

• Remove compatibility code which forced loading all HDUs on close. The old behavior can be used with lazy_load_hdus=False. Because of this change, trying to access the .data attribute from an HDU which is not loaded now raises a IndexError instead of a ValueError. [#6082]

• Deprecated clobber keyword; use overwrite. [#6203]

• Add EXTVER column to the output of HDUList.info(). [#6124]

astropy.modeling

• Removed deprecated Redshift model; Use RedshiftScaleFactor. [#6053]

• Removed deprecated Pix2Sky_AZP.check_mu and Pix2Sky_SZP.check_mu methods. [#6170]

• Deprecated GaussianAbsorption1D model, as it can be better represented by subtracting Gaussian1D from Const1D. [#6200]

• Added method sum_of_implicit_terms to Model, needed when performing a linear fit to a model that has built-in terms with no corresponding parameters (primarily the 1*x term of Shift). [#6174]

astropy.nddata

• Removed deprecated usage of parameter propagate_uncertainties as a positional keyword. [#6170]

• Removed deprecated support_correlated attribute. [#6170]

• Removed deprecated propagate_add, propagate_subtract, propagate_multiply and propagate_divide methods. [#6170]

astropy.stats

• Removed the deprecated sig and varfunc keywords in the sigma_clip function. [#5715]

• Added modify_sample_size keyword to biweight_midvariance function. [#5991]

astropy.table

• In Python 3, when getting an item from a bytestring Column it is now converted to str. This means comparing a single item to a bytes object will always fail, and instead one must compare with a str object. [#5700]

• Removed the deprecated data property of Row. [#5729]

• Removed the deprecated functions join, hstack, vstack and get_groups from np_utils. [#5729]

• Added name parameter to method astropy.table.Table.add_column and names parameter to method astropy.table.Table.add_columns, to provide the flexibility to add unnamed columns, mixin objects and also to specify explicit names. Default names will be used if not specified. [#5996]

• Added optional axis parameter to insert method for Column and MaskedColumn classes. [#6092]

astropy.units

• Moved units.cgs.emu to units.deprecated.emu due to ambiguous definition of “emu”. [#4918, #5906]

• jupiterMass, earthMass, jupiterRad, and earthRad no longer have their prefixed units included in the standard units. If needed, they can still be found in units.deprecated. [#5661]

• solLum,``solMass``, and solRad no longer have their prefixed units included in the standard units. If needed, they can still be found in units.required_by_vounit, and are enabled by default. [#5661]

• Removed deprecated Unit.get_converter. [#6170]

• Internally, astropy replaced use of .to(unit).value with the new to_value(unit) method, since this is somewhat faster. Any subclasses that overwrote .to, should also overwrite .to_value (or possibly just the private ._to_value method. (If you did this, please let us know what was lacking that made this necessary!). [#6137]

astropy.utils

• Removed the deprecated compatibility modules for Python 2.6 (argparse, fractions, gzip, odict, subprocess) [#5975,#6157,#6164]

• Removed the deprecated zest.releaser machinery. [#6282]

astropy.visualization

• Removed the deprecated scale_image function. [#6170]

astropy.vo

• Cone Search now issues deprecation warning because it is moved to Astroquery 0.3.5 and will be removed from Astropy in a future version. [#5558, #5904]

• The astropy.vo.samp package has been moved to astropy.samp, and no longer supports HTTPS/SSL. [#6201, #6213]

astropy.wcs

• Removed deprecated wcs.rotateCD. [#6170]

Bug Fixes

astropy.convolution

• Major change in convolution behavior and keyword arguments: astropy.convolution.convolve was not performing normalized convolution in earlier versions of astropy. [#5782]

• Direct convolution previously implemented the wrong definition of convolution. This error only affects asymmetric kernels. [#6267]

astropy.coordinates

• The astropy.coordinates.Galactic frame had an incorrect ordering for the ‘u’, ‘v’, and ‘w’ cartesian coordinates. [#6330]

• The astropy.coordinates.search_around_sky, astropy.coordinates.search_around_3d, and SkyCoord equivalent methods now correctly yield an astropy.coordinates.Angle as the third return type even if there are no matches (previously it returned a raw Quantity). [#6347]

astropy.io.ascii

• Fix an issue where the fast C-reader was dropping table comments for a table with no data lines. [#8274]

astropy.io.fits

• comments meta key (which is io.ascii’s table convention) is output to COMMENT instead of COMMENTS header. Similarly, COMMENT headers are read into comments meta [#6097]

• Use more sensible fix values for invalid NAXISj header values. [#5935]

• Close file on error to avoid creating a ResourceWarning warning about an unclosed file. [#6168, #6177]

astropy.modeling

• Creating a compound model where one of the submodels is a compound model whose parameters were changed now uses the updated parameters and not the parameters of the original model. [#5741]

• Allow Mapping and Identity to be fittable. [#6018]

• Gaussian models now impose positive stddev in fitting. [#6019]

• OrthoPolynomialBase (Chebyshev2D / Legendre2D) models were being evaluated incorrectly when part of a compound model (using the parameters from the original model), which in turn caused fitting to fail as a no-op. [#6085]

• Allow Ring2D to be defined using r_out. [#6192]

• Make LinearLSQFitter produce correct results with fixed model parameters and allow Shift and Scale to be fitted with LinearLSQFitter and LevMarLSQFitter. [#6174]

astropy.stats

• Allow to choose which median function is used in mad_std and median_absolute_deviation. And allow to use these functions with a multi-dimensional axis. [#5835]

• Fixed biweight_midvariance so that by default it returns a variance that agrees with the standard definition. [#5991]

astropy.table

• Fix a problem with vstack for bytes columns in Python 3. [#5628]

• Fix QTable add/insert row for multidimensional Quantity. [#6092]

astropy.time

• Fixed the initial condition of TimeFITS to allow scale, FITS scale and FITS realization to be checked and equated properly. [#6202]

astropy.visualization

• Fixed a bug that caused the default WCS to return coordinates offset by one. [#6339]

astropy.vo

• Fixed a bug in vo.samp when stopping a hub for which a lockfile was not created. [#6211]

Other Changes and Additions

• Numpy 1.7 and 1.8 are no longer supported. [#6006]

• Python 3.3 is no longer supported. [#6020]

• The bundled ERFA was updated to version 1.4.0. [#6239]

• The bundled version of pytest has now been removed, but the astropy.tests.helper.pytest import will continue to work properly. Affiliated packages should nevertheless transition to importing pytest directly rather than from astropy.tests.helper. This also means that pytest is now a formal requirement for testing for both Astropy and for affiliated packages. [#5694]

Version 1.3.3 (2017-05-29)

Bug Fixes

astropy.coordinates

• Fixed a bug where StaticMatrixTransform erroneously copied frame attributes from the input coordinate to the output frame. In practice, this didn’t actually affect any transforms in Astropy but may change behavior for users who explicitly used the StaticMatrixTransform in their own code. [#6045]

• Fixed get_icrs_coordinates to loop through all the urls in case one raises an exception. [#5864]

astropy.io.fits

• Fix table header not written out properly when fits.writeto() convenience function is used. [#6042]

• Fix writing out read-only arrays. [#6036]

• Extension headers are written out properly when the fits.update() convenience function is used. [#6058]

• Angstrom, erg, G, and barn are no more reported as deprecated FITS units. [#5929]

astropy.table

• Fix problem with Table pprint/pformat raising an exception for non-UTF-8 compliant bytestring data. [#6117]

astropy.units

• Allow strings ‘nan’ and ‘inf’ as Quantity inputs. [#5958]

• Add support for positive and divmod ufuncs (new in numpy 1.13). [#5998, #6020, #6116]

astropy.utils

• On systems that do not have pkg_resources non-numerical additions to version numbers like dev or rc1 are stripped in minversion to avoid a TypeError in distutils.version.LooseVersion [#5944]

• Fix auto_download setting ignored in Time.ut1. [#6033]

astropy.visualization

• Fix bug in ManualInterval which caused the limits to be returned incorrectly if set to zero, and fix defaults for ManualInterval in the presence of NaNs. [#6088]

• Get rid of warnings that occurred when slicing a cube due to the tick locator trying to find ticks for the sliced axis. [#6104]

• Accept normal Matplotlib keyword arguments in set_xlabel and set_ylabel functions. [#5686, #5692, #6060]

• Fix a bug that caused labels to be missing from frames with labels that could change direction mid-axis, such as EllipticalFrame. Also ensure that empty tick labels do not cause any warnings. [#6063]

Version 1.3.2 (2017-03-30)

Bug Fixes

astropy.coordinates

• Ensure that checking equivalence of SkyCoord objects works with non-scalar attributes [#5884, #5887]

• Ensure that transformation to frames with multi-dimensional attributes works as expected [#5890, #5897]

• Make sure all BaseRepresentation objects can be output as strings. [#5889, #5897]

astropy.units

• Add support for heaviside ufunc (new in numpy 1.13). [#5920]

astropy.utils

• Fix to allow the C-based _fast_iterparse() VOTable XML parser to relloc() its buffers instead of overflowing them. [#5824, #5869]

Other Changes and Additions

• File permissions are revised in the released source distribution. [#5912]

Version 1.3.1 (2017-03-18)

New Features

astropy.utils

• The deprecated_renamed_argument decorator got a new pending parameter to suppress the deprecation warnings. [#5761]

Bug Fixes

astropy.coordinates

• Changed SkyCoord so that frame attributes which are not valid for the current frame (but are valid for other frames) are stored on the SkyCoord instance instead of the underlying frame instance (e.g., setting relative_humidity on an ICRS SkyCoord instance.) [#5750]

• Ensured that position_angle and separation give correct answers for frames with different equinox (see #5722). [#5762]

astropy.io.fits

• Fix problem with padding bytes written for BinTable columns converted from unicode [#5280, #5287, #5288, #5296].

• Fix out-of-order TUNITn cards when writing tables to FITS. [#5720]

• Recognize PrimaryHDU when non boolean values are present for the ‘GROUPS’ header keyword. [#5808]

• Fix the insertion of new keywords in compressed image headers (CompImageHeader). [#5866]

astropy.modeling

• Fixed a problem with setting bounding_box on 1D models. [#5718]

• Fixed a broadcasting problem with weighted fitting of 2D models with LevMarLSQFitter. [#5788]

• Fixed a problem with passing kwargs to fitters, specifically verblevel. [#5815]

• Changed FittingWithOutlierRemoval to reject on the residual to the fit [#5831]

astropy.stats

• Fix the psd normalization for Lomb-Scargle periodograms in the presence of noise. [#5713]

• Fix bug in the autofrequency range when minimum_frequency is specified but maximum_frequency is not. [#5738]

• Ensure that a masked array is returned when sigma clipping fully masked data. [#5711]

astropy.table

• Fix problem where key for caching column format function was not sufficiently unique. [#5803]

• Handle sorting NaNs and masked values in jsviewer. [#4052, #5572]

• Ensure mixin columns can be added to a table using a scalar value for the right-hand side if the type supports broadcasting. E.g., for an existing QTable, t['q'] = 3*u.m will now add a column as expected. [#5820]

• Fixes the bug of setting/getting values from rows/columns of a table using numpy array scalars. [#5772]

astropy.units

• Fixed problem where IrreducibleUnits could fail to unpickle. [#5868]

astropy.utils

• Avoid importing ipython in utils.console until it is necessary, to prevent deprecation warnings when importing, e.g., Column. [#5755]

astropy.visualization

• Avoid importing matplotlib.pyplot when importing astropy.visualization.wcsaxes. [#5680, #5684]

• Ignore Numpy warnings that happen in coordinate transforms in WCSAxes. [#5792]

• Fix compatibility issues between WCSAxes and Matplotlib 2.x. [#5786]

• Fix a bug that caused WCSAxes frame visual properties to not be copied over when resetting the WCS. [#5791]

astropy.extern

• Fixed a bug where PLY was overwriting its generated files. [#5728]

Other Changes and Additions

• Fixed a deprecation warning that occurred when running tests with astropy.test(). [#5689]

• The deprecation of the clobber argument (originally deprecated in 1.3.0) in the io.fits write functions was changed to a “pending” deprecation (without displaying warnings) for now. [#5761]

• Updated bundled astropy-helpers to v1.3.1. [#5880]

Version 1.3 (2016-12-22)

New Features

astropy.convolution

• The convolve and convolve_fft arguments now support a mask keyword, which allows them to also support NDData objects as inputs. [#5554]

astropy.coordinates

• Added an of_address classmethod to EarthLocation to enable fast creation of EarthLocation objects given an address by querying the Google maps API [#5154].

• A new routine, get_body_barycentric_posvel has been added that allows one to calculate positions as well as velocities for solar system bodies. For JPL kernels, this roughly doubles the execution time, so if one requires only the positions, one should use get_body_barycentric. [#5231]

• Transformations between coordinate systems can use the more accurate JPL ephemerides. [#5273, #5436]

• Arithmetic on representations, such as addition of two representations, multiplication with a Quantity, or calculating the norm via abs, has now become possible. Furthermore, there are new methods mean, sum, dot, and cross. For all these, the representations are treated as vectors in cartesian space (temporarily converting to CartesianRepresentation if necessary). [#5301] has now become possible. Furthermore, there are news methods mean, sum, dot, and cross with obvious meaning. [#5301] multiplication with a Quantity has now become possible. Furthermore, there are new methods norm, mean, sum, dot, and cross. In all operations, the representations are treated as vectors. They are temporarily converted to CartesianRepresentation if necessary. [#5301]

• CartesianRepresentation can be initialized with plain arrays by passing in a unit. Furthermore, for input with a vector array, the coordinates no longer have to be in the first dimension, but can be at any xyz_axis. To complement the latter, a new get_xyz(xyz_axis) method allows one to get a vector array out along a given axis. [#5439]

astropy.io.ascii

• Files with “Fortran-style” columns (i.e. double-precision scientific notation with a character other than “e”, like 1.495978707D+13) can now be parsed by the fast reader natively. [#5552]

• Allow round-tripping masked data tables in most formats by using an empty string '' as the default representation of masked values when writing. [#5347]

• Allow reading HTML tables with unicode column values in Python 2.7. [#5410]

• Check for self-consistency of ECSV header column names. [#5463]

• Produce warnings when writing an IPAC table from an astropy table that contains metadata not supported by the IPAC format. [#4700]

astropy.io.fits

• “Lazy” loading of HDUs now occurs - when an HDU is requested, the file is only read up to the point where that HDU is found. This can mean a substantial speedup when accessing files that have many HDUs. [#5065]

astropy.io.misc

• Added io.misc.yaml module to support serializing core astropy objects using the YAML protocol. [#5486]

astropy.io.registry

• Added delay_doc_updates contextmanager to postpone the formatting of the documentation for the read and write methods of the class to optionally reduce the import time. [#5275]

astropy.modeling

• Added a class to combine astropy fitters and functions to remove outliers e. g., sigma clip. [#4760]

• Added a Tabular model. [#5105]

• Added Hermite1D and Hermite2D polynomial models [#5242]

• Added the injection of EntryPoints into astropy.modeling.fitting if they inherit from Fitters class. [#5241]

• Added bounding box to Lorentz1D and MexicanHat1D models. [#5393]

• Added Planar2D functional model. [#5456]

• Updated Gaussian2D to accept no arguments (will use default x/y_stddev and theta). [#5537]

astropy.nddata

• Added keep and **kwargs parameter to support_nddata. [#5477]

astropy.stats

• Added axis keyword to biweight_location and biweight_midvariance. [#5127, #5158]

astropy.table

• Allow renaming mixin columns. [#5469]

• Support generalized value formatting for mixin columns in tables. [#5274]

• Support persistence of table indices when pickling and copying table. [#5468]

astropy.tests

• Install both runtime and test dependencies when running the ./setup.py test command. These dependencies are specified by the install_requires and tests_require keywords via setuptools. [#5092]

• Enable easier subclassing of the TestRunner class. [#5505]

astropy.time

• light_travel_time can now use more accurate JPL ephemerides. [#5273, #5436]

astropy.units

• Added pixel_scale and plate_scale equivalencies. [#4987]

• The spectral_density equivalency now supports transformations of luminosity density. [#5151]

• Quantity now accepts strings consisting of a number and unit such as ‘10 km/s’. [#5245]

astropy.utils

• Added a new decorator: deprecated_renamed_argument. This can be used to rename a function argument, while it still allows for the use of the older argument name. [#5214]

astropy.visualization

• Added a make_lupton_rgb function to generate color images from three greyscale images, following the algorithm of Lupton et al. (2004). [#5535]

• Added data and interval inputs to the ImageNormalize class. [#5206]

• Added a new simple_norm convenience function. [#5206]

• Added a default stretch for the Normalization class. [#5206].

• Added a default vmin/vmax for the ManualInterval class. [#5206].

• The wcsaxes subpackage has now been integrated in astropy as astropy.visualization.wcsaxes. This allows plotting of astronomical data/coordinate systems in Matplotlib. [#5496]

astropy.wcs

• Improved footprint_to_file: allow to specify the coordinate system, and use by default the one from RADESYS. Overwrite the file instead of appending to it. [#5494]

API Changes

astropy.convolution

• discretize_model now raises an exception if non-integer ranges are used. Previously it had incorrect behavior but did not raise an exception. [#5538]

astropy.coordinates

• SkyCoord, ICRS, and other coordinate objects, as well as the underlying representations such as SphericalRepresentation and CartesianRepresentation can now be reshaped using methods named like the numpy ones for ndarray (reshape, swapaxes, etc.) [#4123, #5254, #5482]

• The obsgeoloc and obsgeovel attributes of GCRS and PrecessedGeocentric frames are now stored and returned as CartesianRepresentation objects, rather than Quantity objects. Similarly, EarthLocation.get_gcrs_posvel now returns a tuple of CartesianRepresentation objects. [#5253]

• search_around_3d and search_around_sky now return units for the distance matching their input argument when no match is found, instead of dimensionless_unscaled. [#5528]

astropy.io.ascii

• ASCII writers now accept an ‘overwrite’ argument. The default behavior is changed so that a warning will be issued when overwriting an existing file unless overwrite=True. In a future version this will be changed from a warning to an exception to prevent accidentally overwriting a file. [#5007]

• The default representation of masked values when writing tables was changed from '--' to the empty string ''. Previously any user-supplied fill_values parameter would overwrite the class default, but now the values are prepended to the class default. [#5347]

astropy.io.fits

• The old Header interface, deprecated since Astropy 0.1 (PyFITS 3.1), has been removed entirely. See Header Interface Transition Guide for explanations on this change and help on the transition. [#5310]

• The following functions, classes and methods have been removed: CardList, Card.key, Card.cardimage, Card.ascardimage, create_card, create_card_from_string, upper_key, Header.ascard, Header.rename_key, Header.get_history, Header.get_comment, Header.toTxtFile, Header.fromTxtFile, new_table, tdump, tcreate, BinTableHDU.tdump, BinTableHDU.tcreate.

• Removed txtfile argument to the Header constructor.

• Removed usage of Header.update with Header.update(keyword, value, comment) arguments.

• Removed startColumn and endColumn arguments to the FITS_record constructor.

• The clobber argument in FITS writers has been renamed to overwrite. This change affects the following functions and methods: tabledump, writeto, Header.tofile, Header.totextfile, _BaseDiff.report, _BaseHDU.overwrite, BinTableHDU.dump and HDUList.writeto. [#5171]

• Added an optional copy parameter to fits.Header which controls if a copy is made when creating an Header from another Header. [#5005, #5326]

astropy.io.registry

• .fts and .fts.gz files will be automatically identified as io.fits files if no explicit format is given. [#5211]

• Added an optional readwrite parameter for get_formats to filter formats for read or write. [#5275]

astropy.modeling

• Gaussian2D now raises an error if theta is set at the same time as cov_matrix (previously theta was silently ignored). [#5537]

astropy.table

• Setting an existing table column (e.g. t['a'] = [1, 2, 3]) now defaults to replacing the column with a column corresponding to the new value (using t.replace_column()) instead of doing an in-place update. Any existing meta-data in the column (e.g. the unit) is discarded. An in-place update is still done when the new value is not a valid column, e.g. t['a'] = 0. To force an in-place update use the pattern t['a'][:] = [1, 2, 3]. [#5556]

• Allow collections.Mapping-like data attribute when initializing a Table object (dict-like was already possible). [#5213]

astropy.tests

• The inputs to the TestRunner.run_tests() method now must be keyword arguments (no positional arguments). This applies to the astropy.test() function as well. [#5505]

astropy.utils

• Renamed ignored context manager in compat.misc to suppress to be consistent with https://bugs.python.org/issue19266 . [#5003]

astropy.visualization

• Deprecated the scale_image function. [#5206]

• The mpl_normalize module (containing the ImageNormalize class) is now automatically imported with the visualization subpackage. [#5491]

astropy.vo

• The clobber argument in VOSDatabase.to_json() has been renamed to overwrite. [#5171]

astropy.wcs

• wcs.rotateCD() was deprecated without a replacement. [#5240]

Bug Fixes

astropy.coordinates

• Transformations between CIRS and AltAz now correctly account for the location of the observer. [#5591]

• GCRS frames representing a location on Earth with multiple obstimes are now allowed. This means that the solar system routines get_body, get_moon and get_sun now work with non-scalar times and a non-geocentric observer. [#5253]

astropy.io.ascii

• Fix issue with units or other astropy core classes stored in table meta. [#5605]

astropy.io.fits

• Copying a fits.Header using copy or deepcopy from the copy module will use Header.copy to ensure that modifying the copy will not alter the other original Header and vice-versa. [#4990, #5323]

• HDUList.info() no longer raises AttributeError in presence of BZERO. [#5508]

• Avoid exceptions with numpy 1.10 and up when using scaled integer data where BZERO has float type but integer value. [#4639, #5527]

• Converting a header card to a string now calls self.verify('fix+warn') instead of self.verify('fix') so headers with invalid keywords will not raise a VerifyError on printing. [#887,#5054]

• FITS_Record._convert_ascii now converts blank fields to 0 when a non-blank null column value is set. [#5134, #5394]

astropy.io.registry

• read now correctly raises an IOError if a file with an unknown extension can’t be found, instead of raising IORegistryError: “Format could not be identified.” [#4779]

astropy.time

• Ensure Time instances holding a single delta_ut1_utc can be copied, flattened, etc. [#5225]

astropy.units

• Operations involving Angle or Distance, or any other SpecificTypeQuantity instance, now also keep return an instance of the same type if the instance was the second argument (if the resulting unit is consistent with the specific type). [#5327]

• Inplace operations on Angle and Distance instances now raise an exception if the final unit is not equivalent to radian and meter, resp. Similarly, views as Angle and Distance can now only be taken from quantities with appropriate units, and views as Quantity can only be taken from logarithmic quanties such as Magnitude if the physical unit is dimensionless. [#5070]

• Conversion from quantities to logarithmic units now correctly causes a logarithmic quantity such as Magnitude to be returned. [#5183]

astropy.wcs

• SIP distortion for an alternate WCS is correctly initialized now by looking at the “CTYPE” values matching the alternate WCS. [#5443]

Other Changes and Additions

• The bundled ERFA was updated to version 1.3.0. This includes the leap second planned for 2016 Dec 31.

astropy.coordinates

• Initialization of Angle has been sped up for Quantity and Angle input. [#4970]

• The use of np.matrix instances in the transformations has been deprecated, since this class does not allow stacks of matrices. As a result, the semi-public functions angles.rotation_matrix and angles.angle_axis are also deprecated, in favour of the new routines with the same name in coordinates.matrix_utilities. [#5104]

• A new BaseCoordinateFrame.cache dictionary has been created to expose the internal cache. This is useful when modifying representation data in-place without using realize_frame. Additionally, documentation for in-place operations on coordinates were added. [#5575]

• Coordinates and their representations are printed with a slightly different format, following how numpy >= 1.12 prints structured arrays. [#5423]

astropy.cosmology

• The default cosmological model has been changed to Planck 2015, and the citation strings have been updated. [#5372]

astropy.extern

• Updated the bundled six module to version 1.10.0. [#5521]

• Updated the astropy shipped version of PLY to version 3.9. [#5526]

• Updated the astropy shipped version of jQuery to v3.3.1, and dataTables to v1.10.12. [#5564]

astropy.io.fits

• Performance improvements for tables with many columns. [#4985]

• Removed obsolete code that was previously needed to properly implement the append mode. [#4793]

astropy.io.registry

• Reduced the time spent in the get_formats function. This also reduces the time it takes to import astropy subpackages, i.e. astropy.coordinates. [#5262]

astropy.units

• The functions add_enabled_units, set_enabled_equivalencies and add_enabled_equivalencies have been sped up by copying the current _UnitRegistry instead of building it from scratch. [#5306]

• To build the documentation, the build_sphinx command has been deprecated in favor of build_docs. [#5179]

• The --remote-data option to python setup.py test can now take different arguments: --remote-data=none is the same as not specifying --remote-data (skip all tests that require the internet), --remote-data=astropy skips all tests that need remote data except those that require only data from data.astropy.org, and --remote-data=any is the same as --remote-data (run all tests that use remote data). [#5506]

• The pytest recwarn fixture has been removed from the tests in favor of utils.catch_warnings. [#5489]

• Deprecated escape sequences in strings (Python 3.6) have been removed. [#5489]

Version 1.2.2 (2016-12-22)

Bug Fixes

astropy.io.ascii

• Fix a bug where the fill_values parameter was ignored when writing a table to HTML format. [#5379]

astropy.io.fits

• Handle unicode FITS BinTable column names on Python 2 [#5204, #4805]

• Fix reading of float values from ASCII tables, that could be read as float32 instead of float64 (with the E and F formats). These values are now always read as float64. [#5362]

• Fixed memoryleak when using the compression module. [#5399, #5464]

• Able to insert and remove lower case HIERARCH keywords in a consistent manner [#5313, #5321]

astropy.stats

• Fixed broadcasting in sigma_clip when using negative axis. [#4988]

astropy.table

• Assigning a logarithmic unit to a QTable column that did not have a unit yet now correctly turns it into the appropriate function quantity subclass (such as Magnitude or Dex). [#5345]

• Fix default value for show_row_index in Table.show_in_browser. [#5562]

astropy.units

• For inverse trig functions that operate on quantities, catch any warnings that occur from evaluating the function on the unscaled quantity value between __array_prepare__ and __array_wrap__. [#5153]

• Ensure != also works for function units such as MagUnit [#5345]

astropy.wcs

• Fix use of the relax keyword in to_header when used to change the output precision. [#5164]

• wcs.to_header(relax=True) adds a “-SIP” suffix to CTYPE when SIP distortion is present in the WCS object. [#5239]

• Improved log messages in to_header. [#5239]

Other Changes and Additions

• The bundled ERFA was updated to version 1.3.0. This includes the leap second planned for 2016 Dec 31.

astropy.stats

• poisson_conf_interval with 'kraft-burrows-nousek' interval is now faster and usable with SciPy versions < 0.14. [#5064, #5290]

Version 1.2.1 (2016-06-22)

Bug Fixes

astropy.io.fits

• Fixed a bug that caused TFIELDS to not be in the correct position in compressed image HDU headers under certain circumstances, which created invalid FITS files. [#5118, #5125]

astropy.units

• Fixed an ImportError that occurred whenever astropy.constants was imported before astropy.units. [#5030, #5121]

• Magnitude zero points used to define STmag, ABmag, M_bol and m_bol are now collected in astropy.units.magnitude_zero_points. They are not enabled as regular units by default, but can be included using astropy.units.magnitude_zero_points.enable(). This makes it possible to round-trip magnitudes as originally intended. [#5030]

Version 1.2 (2016-06-19)

General

• Astropy now requires Numpy 1.7.0 or later. [#4784]

New Features

astropy.constants

• Add L_bol0, the luminosity corresponding to absolute bolometric magnitude zero. [#4262]

astropy.coordinates

• CartesianRepresentation now includes a transform() method that can take a 3x3 matrix to transform coordinates. [#4860]

• Solar system and lunar ephemerides accessible via get_body, get_body_barycentric and get_moon functions. [#4890]

• Added astrometric frames (i.e., a frame centered on a particular point/object specified in another frame). [#4909, #4941]

• Added SkyCoord.spherical_offsets_to method. [#4338]

• Recent Earth rotation (IERS) data are now auto-downloaded so that AltAz transformations for future dates now use the most accurate available rotation values. [#4436]

• Add support for heliocentric coordinate frames. [#4314]

astropy.cosmology

• angular_diameter_distance_z1z2 now supports the computation of the angular diameter distance between a scalar and an array like argument. [#4593] The method now supports models with negative Omega_k0 (positive curvature universes) [#4661] and allows z2 < z1.

astropy.io.ascii

• File name could be passed as Path object. [#4606]

• Check that columns in formats specifier exist in the output table when writing. [#4508, #4511]

• Allow trailing whitespace in the IPAC header lines. [#4758]

• Updated to filter out the default parser warning of BeautifulSoup. [#4551]

• Added support for reading and writing reStructuredText simple tables. [#4812]

astropy.io.fits

• File name could be passed as Path object. [#4606]

• Header allows a dictionary-like cards argument during creation. [#4663]

• New function convenience.table_to_hdu to allow creating a FITS HDU object directly from an astropy Table. [#4778]

• New optional arguments ignore_missing and remove_all are added to astropy.io.fits.header.remove(). [#5020]

astropy.io.registry

• Added custom IORegistryError. [#4833]

astropy.io.votable

• File name could be passed as Path object. [#4606]

astropy.modeling

• Added the fittable=True attribute to the Scale and Shift models with tests. [#4718]

• Added example plots to docstrings for some built-in models. [#4008]

astropy.nddata

• UnknownUncertainty new subclass of NDUncertainty that can be used to save uncertainties that cannot be used for error propagation. [#4272]

• NDArithmeticMixin: add, subtract, multiply and divide can be used as classmethods but require that two operands are given. These operands don’t need to be NDData instances but they must be convertible to NDData. This conversion is done internally. Using it on the instance does not require (but also allows) two operands. [#4272, #4851]

• NDDataRef new subclass that implements NDData together with all currently available mixins. This class does not implement additional attributes, methods or a numpy.ndarray-like interface like NDDataArray. attributes, methods or a numpy.ndarray-like interface like NDDataArray. [#4797]

astropy.stats

• Added axis keyword for mad_std function. [#4688, #4689]

• Added Bayesian and Akaike Information Criteria. [#4716]

• Added Bayesian upper limits for Poisson count rates. [#4622]

• Added circstats; a module for computing circular statistics. [#3705, #4472]

• Added jackknife resampling method. [#3708, #4439]

• Updated bootstrap to allow bootstrapping statistics with multiple outputs. [#3601]

• Added LombScargle class to compute Lomb-Scargle periodograms [#4811]

astropy.table

• Table.show_in_notebook and Table.show_in_browser(jsviewer=True) now yield tables with an “idx” column, allowing easy identification of the index of a row even when the table is re-sorted in the browser. [#4404]

• Added AttributeError when trying to set mask on non-masked table. [#4637]

• Allow to use a tuple of keys in Table.sort. [#4671]

• Added itercols; a way to iterate through columns of a table. [#3805, #4888]

• Table.show_in_notebook and the default notebook display (i.e., Table._repr_html_) now use consistent table styles which can be set using the astropy.table.default_notebook_table_class configuration item. [#4886]

• Added interface to create Table directly from any table-like object that has an __astropy_table__ method. [#4885]

astropy.tests

• Enable test runner to obtain documentation source files from directory other than “docs”. [#4748]

astropy.time

• Added caching of scale and format transformations for improved performance. [#4422]

• Recent Earth rotation (IERS) data are now auto-downloaded so that UT1 transformations for future times now work out of the box. [#4436]

• Add support for barycentric/heliocentric time corrections. [#4314]

astropy.units

• The option to use tuples to indicate fractional powers of units, deprecated in 0.3.1, has been removed. [#4449]

• Added slug to imperial units. [#4670]

• Added Earth radius (R_earth) and Jupiter radius (R_jup) to units. [#4818]

• Added a represents property to allow access to the definition of a named unit (e.g., u.kpc.represents yields 1000 pc). [#4806]

• Add bolometric absolute and apparent magnitudes, M_bol and m_bol. [#4262]

astropy.utils

• Path object could be passed to get_readable_fileobj. [#4606]

• Implemented a generic and extensible way of merging metadata. [#4459]

• Added format_doc decorator which allows to replace and/or format the current docstring of an object. [#4242]

• Added a new context manager set_locale to temporarily set the current locale. [#4363]

• Added new IERS_Auto class to auto-download recent IERS (Earth rotation) data when required by coordinate or time transformations. [#4436]

astropy.visualization

• Add zscale interval based on Numdisplay’s implementation. [#4776]

API changes

astropy.config

• The deprecated ConfigurationItem and ConfigAlias classes and the save_config, get_config_items, and generate_all_config_items functions have now been removed. [#2767, #4446]

astropy.coordinates

• Removed compatibility layer for pre-v0.4 API. [#4447]

• Added copy keyword-only argument to allow initialization without copying the (possibly large) input coordinate arrays. [#4883]

astropy.cosmology

• Improve documentation of z validity range of cosmology objects [#4882, #4949]

astropy.io.ascii

• Add a way to control HTML escaping when writing a table as an HTML file. [#4423]

astropy.io.fits

• Two optional boolean arguments ignore_missing and remove_all are added to Header.remove. [#5020]

astropy.modeling

• Renamed Redshift model to RedshiftScaleFactor. [#3672]

• Inputs (coords and out) to render function in Model are converted to float. [#4697]

• RotateNative2Celestial and RotateCelestial2Native are now implemented as subclasses of EulerAngleRotation. [#4881, #4940]

astropy.nddata

• NDDataBase does not set the private uncertainty property anymore. This only affects you if you subclass NDDataBase directly. [#4270]

• NDDataBase: the uncertainty-setter is removed. A similar one is added in NDData so this also only affects you if you subclassed NDDataBase directly. [#4270]

• NDDataBase: uncertainty-getter returns None instead of the private uncertainty and is now abstract. This getter is moved to NDData so it only affects direct subclasses of NDDataBase. [#4270]

• NDData accepts a Quantity-like data and an explicitly given unit. Before a ValueError was raised in this case. The final instance will use the explicitly given unit-attribute but doesn’t check if the units are convertible and the data will not be scaled. [#4270]

• NDData : the given mask, explicit or implicit if the data was masked, will be saved by the setter. It will not be saved directly as the private attribute. [#4879]

• NDData accepts an additional argument copy which will copy every parameter before it is saved as attribute of the instance. [#4270]

• NDData: added an uncertainty.getter that returns the private attribute. It is equivalent to the old NDDataBase.uncertainty-getter. [#4270]

• NDData: added an uncertainty.setter. It is slightly modified with respect to the old NDDataBase.uncertainty-setter. The changes include:

• if the uncertainty has no uncertainty_type an info message is printed instead of a TypeError and the uncertainty is saved as UnknownUncertainty except the uncertainty is None. [#4270]

• the requirement that the uncertainty_type of the uncertainty needs to be a string was removed. [#4270]

• if the uncertainty is a subclass of NDUncertainty the parent_nddata attribute will be set so the uncertainty knows to which data it belongs. This is also a Bugfix. [#4152, #4270]

• NDData: added a meta-getter, which will set and return an empty OrderedDict if no meta was previously set. [#4509, #4469]

• NDData: added an meta-setter. It requires that the meta is dictionary-like (it also accepts Headers or ordered dictionaries and others) or None. [#4509, #4469, #4921]

• NDArithmeticMixin: The operand in arithmetic methods (add, …) doesn’t need to be a subclass of NDData. It is sufficient if it can be converted to one. This conversion is done internally. [#4272]

• NDArithmeticMixin: The arithmetic methods allow several new arguments to control how or if different attributes of the class will be processed during the operation. [#4272]

• NDArithmeticMixin: Giving the parameter propagate_uncertainties as positional keyword is deprecated and will be removed in the future. You now need to specify it as keyword-parameter. Besides True and False also None is now a valid value for this parameter. [#4272, #4851]

• NDArithmeticMixin: The wcs attribute of the operands is not compared and thus raises no ValueError if they differ, except if a compare_wcs parameter is specified. [#4272]

• NDArithmeticMixin: The arithmetic operation was split from a general _arithmetic method to different specialized private methods to allow subclasses more control on how the attributes are processed without overriding _arithmetic. The _arithmetic method is now used to call these other methods. [#4272]

• NDSlicingMixin: If the attempt at slicing the mask, wcs or uncertainty fails with a TypeError a Warning is issued instead of the TypeError. [#4271]

• NDUncertainty: support_correlated attribute is deprecated in favor of supports_correlated which is a property. Also affects StdDevUncertainty. [#4272]

• NDUncertainty: added the __init__ that was previously implemented in StdDevUncertainty and takes an additional unit parameter. [#4272]

• NDUncertainty: added a unit property without setter that returns the set unit or if not set the unit of the parent. [#4272]

• NDUncertainty: included a parent_nddata property similar to the one previously implemented in StdDevUncertainty. [#4272]

• NDUncertainty: added an array property with setter. The setter will convert the value to a plain numpy array if it is a list or a subclass of a numpy array. [#4272]

• NDUncertainty: propagate_multiply and similar were removed. Before they were abstract properties and replaced by methods with the same name but with a leading underscore. The entry point for propagation is a method called propagate. [#4272]

• NDUncertainty and subclasses: implement a representation (__repr__). [#4787]

• StdDevUncertainty: error propagation allows an explicitly given correlation factor, which may be a scalar or an array which will be taken into account during propagation. This correlation must be determined manually and is not done by the uncertainty! [#4272]

• StdDevUncertainty: the array is converted to a plain numpy array only if it’s a list or a subclass of numpy.ndarray. Previously it was always cast to a numpy array but also allowed subclasses. [#4272]

• StdDevUncertainty: setting the parent_nddata does not compare if the shape of it’s array is identical to the parents data shape. [#4272]

• StdDevUncertainty: the array.setter doesn’t compare if the array has the same shape as the parents data. [#4272]

• StdDevUncertainty: deprecated support_correlated in favor of supports_correlated. [#4272, #4828]

• StdDevUncertainty: deprecated propagate_add and similar methods in favor of propagate. [#4272, #4828]

• Allow data to be a named argument in NDDataArray. [#4626]

astropy.table

• operations.unique now has a keep parameter, which allows one to select whether to keep the first or last row in a set of duplicate rows, or to remove all rows that are duplicates. [#4632]

• QTable now behaves more consistently by making columns act as a Quantity even if they are assigned a unit after the table is created. [#4497, #4884]

astropy.units

• Remove deprecated register argument for Unit classes. [#4448]

astropy.utils

• The astropy.utils.compat.argparse module has now been deprecated. Use the Python ‘argparse’ module directly instead. [#4462]

• The astropy.utils.compat.odict module has now been deprecated. Use the Python ‘collections’ module directly instead. [#4466]

• The astropy.utils.compat.gzip module has now been deprecated. Use the Python ‘gzip’ module directly instead. [#4464]

• The deprecated ScienceStateAlias class has been removed. [#2767, #4446]

• The astropy.utils.compat.subprocess module has now been deprecated. Use the Python ‘subprocess’ module instead. [#4483]

• The astropy.utils.xml.unescaper module now also unescapes '%2F' to '/' and '&&' to '&' in a given URL. [#4699]

• The astropy.utils.metadata.MetaData descriptor has now two optional parameters: doc and copy. [#4921]

• The default IERS (Earth rotation) data now is now auto-downloaded via a new class IERS_Auto. When extrapolating UT1-UTC or polar motion values outside the available time range, the values are now clipped at the last available value instead of being linearly extrapolated. [#4436]

astropy.wcs

• WCS objects can now be initialized with an ImageHDU or PrimaryHDU object. [#4493, #4505]

• astropy.wcs now issues an INFO message when the header has SIP coefficients but “-SIP” is missing from CTYPE. [#4814]

Bug fixes

astropy.coordinates

• Ameliorate a problem with get_sun not round-tripping due to approximations in the light deflection calculation. [#4952]

• Ensure that angle_utilities.position_angle accepts floats, as stated in the docstring. [#3800]

• Ensured that transformations for GCRS frames are correct for non-geocentric observers. [#4986]

• Fixed a problem with the Quantity._repr_latex_ method causing errors when showing an EarthLocation in a Jupyter notebook. [#4542, #5068]

astropy.io.ascii

• Fix a problem where the fast reader (with use_fast_converter=False) can fail on non-US locales. [#4363]

• Fix astropy.io.ascii.read handling of units for IPAC formatted files. Columns with no unit are treated as unitless not dimensionless. [#4867, #4947]

• Fix problems the header parsing in the sextractor reader. [#4603, #4910]

astropy.io.fits

• GroupsHDU.is_image property is now set to False. [#4742]

• Ensure scaling keywords are removed from header when unsigned integer data is converted to signed type. [#4974, #5053]

• Made TFORMx keyword check more flexible in test of compressed images to enable compatibility of the test with cfitsio 3.380. [#4646, #4653]

astropy.io.votable

• The astropy.io.votable.validator.html module is updated to handle division by zero when generating validation report. [#4699]

• KeyError when converting Table v1.2 numeric arrays fixed. [#4782]

astropy.modeling

• Refactored AiryDisk2D, Sersic1D, and Sersic2D models to be able to combine them as classes as well as instances. [#4720]

• Modified the “LevMarLSQFitter” class to use the weights in the calculation of the Jacobian. [#4751]

astropy.nddata

• NDData giving masked_Quantities as data-argument will use the implicitly passed mask, unit and value. [#4270]

• NDData using a subclass implementing NDData with NDArithmeticMixin now allows error propagation. [#4270]

• Fixed memory leak that happened when uncertainty of NDDataArray was set. [#4825, #4862]

• StdDevUncertainty: During error propagation the unit of the uncertainty is taken into account. [#4272]

• NDArithmeticMixin: divide and multiply yield correct uncertainties if only one uncertainty is set. [#4152, #4272]

astropy.stats

• Fix sigma_clipped_stats to use the axis argument. [#4726, #4808]

astropy.table

• Fixed bug where Tables created from existing Table objects were not inheriting the primary_key attribute. [#4672, #4930]

• Provide more detail in the error message when reading a table fails due to a problem converting column string values. [#4759]

astropy.units

• Exponentiation using a Quantity with a unit equivalent to dimensionless as base and an array-like exponent yields the correct result. [#4770]

• Ensured that with spectral_density equivalency one could also convert between photlam and STmag/ABmag. [#5017]

astropy.utils

• The astropy.utils.compat.fractions module has now been deprecated. Use the Python ‘fractions’ module directly instead. [#4463]

• Added format_doc decorator which allows to replace and/or format the current docstring of an object. [#4242]

• Attributes using the astropy.utils.metadata.MetaData descriptor are now included in the sphinx documentation. [#4921]

astropy.vo

• Relaxed expected accuracy of Cone Search prediction test to reduce spurious failures. [#4382]

astropy.wcs

• astropy.wcs.to_header removes “-SIP” from CTYPE when SIP coefficients are not written out, i.e. relax is either False or None. astropy.wcs.to_header appends “-SIP” to CTYPE when SIP coefficients are written out, i.e. relax=True. [#4814]

• Made wcs.bounds_check call wcsprm_python2c, which means it works even if wcs.set has not been called yet. [#4957, #4966].

• WCS objects can no longer be reverse-indexed, which was technically permitted but incorrectly implemented previously [#4962]

Other Changes and Additions

• Python 2.6 is no longer supported. [#4486]

• The bundled version of py.test has been updated to 2.8.3. [#4349]

• Reduce Astropy’s import time (import astropy) by almost a factor 2. [#4649]

• Cython prerequisite for building changed to v0.19 in install.rst [#4705, #4710, #4719]

• All astropy.modeling functionality that was deprecated in Astropy 1.0 has been removed. [#4857]

• Added instructions for installing Astropy into CASA. [#4840]

• Added an example gallery to the docs demonstrating short snippets/examples. [#4734]

Version 1.1.2 (2016-03-10)

New Features

astropy.wcs

• The astropy.wcs module now exposes WCSHDO_P* constants that can be used to allow more control over output precision when using the relax keyword argument. [#4616]

Bug Fixes

astropy.io.ascii

• Fixed handling of CDS data file when no description is given and also included stripping out of markup for missing value from description. [#4437, #4474]

astropy.io.fits

• Fixed possible segfault during error handling in FITS tile compression. [#4489]

• Fixed crash on pickling of binary table columns with the ‘X’, ‘P’, or ‘Q’ format. [#4514]

• Fixed memory / reference leak that could occur when copying a FITS_rec object (the .data for table HDUs). [#520]

• Fixed a memory / reference leak in FITS_rec that occurred in a wide range of cases, especially after writing FITS tables to a file, but in other cases as well. [#4539]

astropy.modeling

• Fix a bug to allow instantiation of a modeling class having a parameter with a custom setter that takes two parameters (value, model) [#4656]

astropy.table

• Fixed bug when replacing a table column with a mixin column like Quantity or Time. [#4601]

• Disable initial ordering in jsviewer (show_in_browser, show_in_notebook) to respect the order from the Table. [#4628]

astropy.units

• Fixed sphinx issues on plotting quantities. [#4527]

astropy.utils

• Fixed latex representation of function units. [#4563]

• The zest.releaser hooks included in Astropy are now injected locally to Astropy, rather than being global. [#4650]

astropy.visualization

• Fixed fits2bitmap script to allow ext flag to contain extension names or numbers. [#4468]

• Fixed fits2bitmap default output filename generation for compressed FITS files. [#4468]

• Fixed quantity_support to ensure its conversion returns ndarray instances (needed for numpy >=1.10). [#4654]

astropy.wcs

• Fixed possible exception in handling of SIP headers that was introduced in v1.1.1. [#4492]

• Fixed a bug that caused WCS objects with a high dynamic range of values for certain parameters to lose precision when converted to a header. This occurred for example in cases of spectral cubes, where a spectral axis in Hz might have a CRVAL3 value greater than 1e10 but the spatial coordinates would have CRVAL1/2 values 8 to 10 orders of magnitude smaller. This bug was present in Astropy 1.1 and 1.1.1 but not 1.0.x. This has now been fixed by ensuring that all WCS keywords are output with 14 significant figures by default. [#4616]

Other Changes and Additions

• Updated bundled astropy-helpers to v1.1.2. [#4678]

• Updated bundled copy of WCSLIB to 5.14. [#4579]

Version 1.1.1 (2016-01-08)

New Features

astropy.io.registry

• Allow pathlib.Path objects (available in Python 3.4 and later) for specifying the file name in registry read / write functions. [#4405]

astropy.utils

• console.human_file_size now accepts quantities with byte-equivalent units [#4373]

Bug Fixes

astropy.analytic_functions

• Fixed the blackbody functions’ handling of overflows on some platforms (Windows with MSVC, older Linux versions) with a buggy expm1 function. [#4393]

astropy.io.fits

• Fixed an bug where updates to string columns in FITS tables were not saved on Python 3. [#4452]

Other Changes and Additions

• Updated bundled astropy-helpers to v1.1.1. [#4413]

Version 1.1 (2015-12-11)

New Features

astropy.config

• Added new tools set_temp_config and set_temp_cache which can be used either as function decorators or context managers to temporarily use alternative directories in which to read/write the Astropy config files and download caches respectively. This is especially useful for testing, though set_temp_cache may also be used as a way to provide an alternative (application specific) download cache for large data files, rather than relying on the default cache location in users’ home directories. [#3975]

astropy.constants

• Added the Thomson scattering cross-section. [#3839]

astropy.convolution

• Added Moffat2DKernel. [#3965]

astropy.coordinates

• Added get_constellation function and SkyCoord.get_constellation convenience method to determine the constellation that a coordinate is in. [#3758]

• Added PrecessedGeocentric frame, which is based on GCRS, but precessed to a specific requested mean equinox. [#3758]

• Added Supergalactic frame to support de Vaucouleurs supergalactic coordinates. [#3892]

• SphericalRepresentation now has a ._unit_representation class attribute to specify an equivalent UnitSphericalRepresentation. This allows subclasses of representations to pair up correctly. [#3757]

• Added functionality to support getting the locations of observatories by name. See astropy.coordinates.EarthLocation.of_site. [#4042]

• Added ecliptic coordinates, including GeocentricTrueEcliptic, BarycentricTrueEcliptic, and HeliocentricTrueEcliptic. [#3749]

astropy.cosmology

• Add Planck 2015 cosmology [#3476]

• Distance calculations now > 20-40x faster for the supplied cosmologies due to implementing Cython scalar versions of FLRW.inv_efunc.[#4127]

astropy.io.ascii

• Automatically use guess=False when reading if the file format is provided and the format parameters are uniquely specified. This update also removes duplicate format guesses to improve performance. [#3418]

• Calls to ascii.read() for fixed-width tables may now omit one of the keyword arguments col_starts or col_ends. Columns will be assumed to begin and end immediately adjacent to each other. [#3657]

• Add a function get_read_trace() that returns a traceback of the attempted read formats for the last call to astropy.io.ascii.read. [#3688]

• Supports LZMA decompression via get_readable_fileobj [#3667]

• Allow - character is Sextractor format column names. [#4168]

• Improve DAOphot reader to read multi-aperture files [#3535, #4207]

astropy.io.fits

• Support reading and writing from bzip2 compressed files. i.e. .fits.bz2 files. [#3789]

• Included a new command-line script called fitsinfo to display a summary of the HDUs in one or more FITS files. [#3677]

astropy.io.misc

• Support saving all meta information, description and units of tables and columns in HDF5 files [#4103]

astropy.io.votable

• A new method was added to astropy.io.votable.VOTable, get_info_by_id to conveniently find an INFO element by its ID attribute. [#3633]

• Instances in the votable tree now have better __repr__ methods. [#3639]

astropy.logger.py

• Added log levels (e.g., DEBUG, INFO, CRITICAL) to astropy.log [#3947]

astropy.modeling

• Added a new Parameter.validator interface for setting a validation method on individual model parameters. See the Parameter documentation for more details. [#3910]

• The projection classes that are named based on the 3-letter FITS WCS projections (e.g. Pix2Sky_TAN) now have aliases using longer, more descriptive names (e.g. Pix2Sky_Gnomonic). [#3583]

• All of the standard FITS WCS projection types have been implemented in astropy.modeling.projections (by wrapping WCSLIB). [#3906]

• Added Sersic1D and Sersic2D model classes. [#3889]

• Added the Voigt profile to existing models. [#3901]

• Added bounding_box property and render_model function [#3909]

astropy.nddata

• Added block_reduce and block_replicate functions. [#3453]

• extract_array now offers different options to deal with array boundaries [#3727]

• Added a new Cutout2D class to create postage stamp image cutouts with optional WCS propagation. [#3823]

astropy.stats

• Added sigma_lower and sigma_upper keywords to sigma_clip to allow for non-symmetric clipping. [#3595]

• Added cenfunc, stdfunc, and axis keywords to sigma_clipped_stats. [