Source code for astropy.coordinates.builtin_frames.ecliptic

# -*- coding: utf-8 -*-
# Licensed under a 3-clause BSD style license - see LICENSE.rst

from astropy import units as u
from astropy.utils.decorators import format_doc
from astropy.coordinates import representation as r
from astropy.coordinates.baseframe import BaseCoordinateFrame, RepresentationMapping, base_doc
from astropy.coordinates.attributes import TimeAttribute, QuantityAttribute
from .utils import EQUINOX_J2000, DEFAULT_OBSTIME

__all__ = ['GeocentricMeanEcliptic', 'BarycentricMeanEcliptic',
           'HeliocentricMeanEcliptic', 'BaseEclipticFrame',
           'GeocentricTrueEcliptic', 'BarycentricTrueEcliptic',
           'HeliocentricTrueEcliptic',
           'HeliocentricEclipticIAU76', 'CustomBarycentricEcliptic']


doc_components_ecl = """
    lon : `Angle`, optional, must be keyword
        The ecliptic longitude for this object (``lat`` must also be given and
        ``representation`` must be None).
    lat : `Angle`, optional, must be keyword
        The ecliptic latitude for this object (``lon`` must also be given and
        ``representation`` must be None).
    distance : `~astropy.units.Quantity`, optional, must be keyword
        The distance for this object from the {0}.
        (``representation`` must be None).

    pm_lon_coslat : `Angle`, optional, must be keyword
        The proper motion in the ecliptic longitude (including the ``cos(lat)``
        factor) for this object (``pm_lat`` must also be given).
    pm_lat : `Angle`, optional, must be keyword
        The proper motion in the ecliptic latitude for this object
        (``pm_lon_coslat`` must also be given).
    radial_velocity : :class:`~astropy.units.Quantity`, optional, must be keyword
        The radial velocity of this object.
"""


[docs]@format_doc(base_doc, components=doc_components_ecl.format('specified location'), footer="") class BaseEclipticFrame(BaseCoordinateFrame): """ A base class for frames that have names and conventions like that of ecliptic frames. .. warning:: In the current version of astropy, the ecliptic frames do not yet have stringent accuracy tests. We recommend you test to "known-good" cases to ensure this frames are what you are looking for. (and then ideally you would contribute these tests to Astropy!) """ default_representation = r.SphericalRepresentation default_differential = r.SphericalCosLatDifferential
doc_footer_geo = """ Other parameters ---------------- equinox : `~astropy.time.Time`, optional The date to assume for this frame. Determines the location of the x-axis and the location of the Earth (necessary for transformation to non-geocentric systems). Defaults to the 'J2000' equinox. obstime : `~astropy.time.Time`, optional The time at which the observation is taken. Used for determining the position of the Earth. Defaults to J2000. """
[docs]@format_doc(base_doc, components=doc_components_ecl.format('geocenter'), footer=doc_footer_geo) class GeocentricMeanEcliptic(BaseEclipticFrame): """ Geocentric mean ecliptic coordinates. These origin of the coordinates are the geocenter (Earth), with the x axis pointing to the *mean* (not true) equinox at the time specified by the ``equinox`` attribute, and the xy-plane in the plane of the ecliptic for that date. Be aware that the definition of "geocentric" here means that this frame *includes* light deflection from the sun, aberration, etc when transforming to/from e.g. ICRS. The frame attributes are listed under **Other Parameters**. """ equinox = TimeAttribute(default=EQUINOX_J2000) obstime = TimeAttribute(default=DEFAULT_OBSTIME)
[docs]@format_doc(base_doc, components=doc_components_ecl.format('geocenter'), footer=doc_footer_geo) class GeocentricTrueEcliptic(BaseEclipticFrame): """ Geocentric true ecliptic coordinates. These origin of the coordinates are the geocenter (Earth), with the x axis pointing to the *true* (not mean) equinox at the time specified by the ``equinox`` attribute, and the xy-plane in the plane of the ecliptic for that date. Be aware that the definition of "geocentric" here means that this frame *includes* light deflection from the sun, aberration, etc when transforming to/from e.g. ICRS. The frame attributes are listed under **Other Parameters**. """ equinox = TimeAttribute(default=EQUINOX_J2000) obstime = TimeAttribute(default=DEFAULT_OBSTIME)
doc_footer_bary = """ Other parameters ---------------- equinox : `~astropy.time.Time`, optional The date to assume for this frame. Determines the location of the x-axis and the location of the Earth and Sun. Defaults to the 'J2000' equinox. """
[docs]@format_doc(base_doc, components=doc_components_ecl.format("barycenter"), footer=doc_footer_bary) class BarycentricMeanEcliptic(BaseEclipticFrame): """ Barycentric mean ecliptic coordinates. These origin of the coordinates are the barycenter of the solar system, with the x axis pointing in the direction of the *mean* (not true) equinox as at the time specified by the ``equinox`` attribute (as seen from Earth), and the xy-plane in the plane of the ecliptic for that date. The frame attributes are listed under **Other Parameters**. """ equinox = TimeAttribute(default=EQUINOX_J2000)
[docs]@format_doc(base_doc, components=doc_components_ecl.format("barycenter"), footer=doc_footer_bary) class BarycentricTrueEcliptic(BaseEclipticFrame): """ Barycentric true ecliptic coordinates. These origin of the coordinates are the barycenter of the solar system, with the x axis pointing in the direction of the *true* (not mean) equinox as at the time specified by the ``equinox`` attribute (as seen from Earth), and the xy-plane in the plane of the ecliptic for that date. The frame attributes are listed under **Other Parameters**. """ equinox = TimeAttribute(default=EQUINOX_J2000)
doc_footer_helio = """ Other parameters ---------------- equinox : `~astropy.time.Time`, optional The date to assume for this frame. Determines the location of the x-axis and the location of the Earth and Sun. Defaults to the 'J2000' equinox. obstime : `~astropy.time.Time`, optional The time at which the observation is taken. Used for determining the position of the Sun. Defaults to J2000. """
[docs]@format_doc(base_doc, components=doc_components_ecl.format("sun's center"), footer=doc_footer_helio) class HeliocentricMeanEcliptic(BaseEclipticFrame): """ Heliocentric mean ecliptic coordinates. These origin of the coordinates are the center of the sun, with the x axis pointing in the direction of the *mean* (not true) equinox as at the time specified by the ``equinox`` attribute (as seen from Earth), and the xy-plane in the plane of the ecliptic for that date. The frame attributes are listed under **Other Parameters**. {params} """ equinox = TimeAttribute(default=EQUINOX_J2000) obstime = TimeAttribute(default=DEFAULT_OBSTIME)
[docs]@format_doc(base_doc, components=doc_components_ecl.format("sun's center"), footer=doc_footer_helio) class HeliocentricTrueEcliptic(BaseEclipticFrame): """ Heliocentric true ecliptic coordinates. These origin of the coordinates are the center of the sun, with the x axis pointing in the direction of the *true* (not mean) equinox as at the time specified by the ``equinox`` attribute (as seen from Earth), and the xy-plane in the plane of the ecliptic for that date. The frame attributes are listed under **Other Parameters**. {params} """ equinox = TimeAttribute(default=EQUINOX_J2000) obstime = TimeAttribute(default=DEFAULT_OBSTIME)
[docs]@format_doc(base_doc, components=doc_components_ecl.format("sun's center"), footer="") class HeliocentricEclipticIAU76(BaseEclipticFrame): """ Heliocentric mean (IAU 1976) ecliptic coordinates. These origin of the coordinates are the center of the sun, with the x axis pointing in the direction of the *mean* (not true) equinox of J2000, and the xy-plane in the plane of the ecliptic of J2000 (according to the IAU 1976/1980 obliquity model). It has, therefore, a fixed equinox and an older obliquity value than the rest of the frames. The frame attributes are listed under **Other Parameters**. {params} """ obstime = TimeAttribute(default=DEFAULT_OBSTIME)
[docs]@format_doc(base_doc, components=doc_components_ecl.format("barycenter"), footer="") class CustomBarycentricEcliptic(BaseEclipticFrame): """ Barycentric ecliptic coordinates with custom obliquity. These origin of the coordinates are the barycenter of the solar system, with the x axis pointing in the direction of the *mean* (not true) equinox of J2000, and the xy-plane in the plane of the ecliptic tilted a custom obliquity angle. The frame attributes are listed under **Other Parameters**. """ obliquity = QuantityAttribute(default=84381.448 * u.arcsec, unit=u.arcsec)