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
from .utils import EQUINOX_J2000, DEFAULT_OBSTIME
__all__ = ['GeocentricTrueEcliptic', 'BarycentricTrueEcliptic',
'HeliocentricTrueEcliptic', 'BaseEclipticFrame']
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.
"""
[docs]@format_doc(base_doc, components=doc_components_ecl.format('geocenter'),
footer=doc_footer_geo)
class GeocentricTrueEcliptic(BaseEclipticFrame):
"""
Geocentric 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)
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 BarycentricTrueEcliptic(BaseEclipticFrame):
"""
Barycentric 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.
"""
[docs]@format_doc(base_doc, components=doc_components_ecl.format("sun's center"),
footer=doc_footer_helio)
class HeliocentricTrueEcliptic(BaseEclipticFrame):
"""
Heliocentric 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)