Source code for astropy.timeseries.io.kepler

# Licensed under a 3-clause BSD style license - see LICENSE.rst
import warnings

import numpy as np

from astropy.io import registry, fits
from astropy.table import Table, MaskedColumn
from astropy.time import Time, TimeDelta

from astropy.timeseries.sampled import TimeSeries

__all__ = ["kepler_fits_reader"]


[docs]def kepler_fits_reader(filename): """ This serves as the FITS reader for KEPLER or TESS files within astropy-timeseries. This function should generally not be called directly, and instead this time series reader should be accessed with the :meth:`~astropy.timeseries.TimeSeries.read` method:: >>> from astropy.timeseries import TimeSeries >>> ts = TimeSeries.read('kplr33122.fits', format='kepler.fits') # doctest: +SKIP Parameters ---------- filename : `str` or `pathlib.Path` File to load. Returns ------- ts : `~astropy.timeseries.TimeSeries` Data converted into a TimeSeries. """ hdulist = fits.open(filename) # Get the lightcurve HDU telescope = hdulist[0].header['telescop'].lower() if telescope == 'tess': hdu = hdulist['LIGHTCURVE'] elif telescope == 'kepler': hdu = hdulist[1] else: raise NotImplementedError("{} is not implemented, only KEPLER or TESS are " "supported through this reader".format(hdulist[0].header['telescop'])) if hdu.header['EXTVER'] > 1: raise NotImplementedError("Support for {} v{} files not yet " "implemented".format(hdu.header['TELESCOP'], hdu.header['EXTVER'])) # Check time scale if hdu.header['TIMESYS'] != 'TDB': raise NotImplementedError("Support for {} time scale not yet " "implemented in {} reader".format(hdu.header['TIMESYS'], hdu.header['TELESCOP'])) tab = Table.read(hdu, format='fits') # Some KEPLER files have a T column instead of TIME. if "T" in tab.colnames: tab.rename_column("T", "TIME") for colname in tab.colnames: unit = tab[colname].unit # Make masks nan for any column which will turn into a Quantity # later. TODO: remove once we support Masked Quantities properly? if unit and isinstance(tab[colname], MaskedColumn): tab[colname] = tab[colname].filled(np.nan) # Fix units if unit == 'e-/s': tab[colname].unit = 'electron/s' if unit == 'pixels': tab[colname].unit = 'pixel' # Rename columns to lowercase tab.rename_column(colname, colname.lower()) # Filter out NaN rows nans = np.isnan(tab['time'].data) if np.any(nans): warnings.warn(f'Ignoring {np.sum(nans)} rows with NaN times') tab = tab[~nans] # Time column is dependent on source and we correct it here reference_date = Time(hdu.header['BJDREFI'], hdu.header['BJDREFF'], scale=hdu.header['TIMESYS'].lower(), format='jd') time = reference_date + TimeDelta(tab['time'].data) time.format = 'isot' # Remove original time column tab.remove_column('time') hdulist.close() return TimeSeries(time=time, data=tab)
registry.register_reader('kepler.fits', TimeSeries, kepler_fits_reader) registry.register_reader('tess.fits', TimeSeries, kepler_fits_reader)