GeocentricMeanEcliptic

class astropy.coordinates.builtin_frames.GeocentricMeanEcliptic(*args, copy=True, representation_type=None, differential_type=None, **kwargs)[source]

Bases: astropy.coordinates.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.

Parameters:
data : BaseRepresentation subclass instance

A representation object or None to have no data (or use the coordinate component arguments, see below).

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 : Quantity, optional, must be keyword

The distance for this object from the geocenter. (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 : Quantity, optional, must be keyword

The radial velocity of this object.

representation_type : BaseRepresentation subclass, str, optional

A representation class or string name of a representation class. This sets the expected input representation class, thereby changing the expected keyword arguments for the data passed in. For example, passing representation_type='cartesian' will make the classes expect position data with cartesian names, i.e. x, y, z in most cases unless overriden via frame_specific_representation_info. To see this frame’s names, check out <this frame>().representation_info.

differential_type : BaseDifferential subclass, str, dict, optional

A differential class or dictionary of differential classes (currently only a velocity differential with key ‘s’ is supported). This sets the expected input differential class, thereby changing the expected keyword arguments of the data passed in. For example, passing differential_type='cartesian' will make the classes expect velocity data with the argument names v_x, v_y, v_z unless overriden via frame_specific_representation_info. To see this frame’s names, check out <this frame>().representation_info.

copy : bool, optional

If True (default), make copies of the input coordinate arrays. Can only be passed in as a keyword argument.

Other Parameters:
 
equinox : 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 : Time, optional

The time at which the observation is taken. Used for determining the position of the Earth. Defaults to J2000.

Attributes Summary

default_differential
default_representation
equinox
frame_attributes
frame_specific_representation_info
name
obstime

Attributes Documentation

default_differential
default_representation
equinox = <Time object: scale='tt' format='jyear_str' value=J2000.000>
frame_attributes = {'equinox': <astropy.coordinates.attributes.TimeAttribute object>, 'obstime': <astropy.coordinates.attributes.TimeAttribute object>}
frame_specific_representation_info
name = 'geocentricmeanecliptic'
obstime = <Time object: scale='tt' format='jyear_str' value=J2000.000>