# HeliocentricMeanEcliptic¶

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

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}

Parameters
dataBaseRepresentation subclass instance

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

lonAngle, optional, must be keyword

The ecliptic longitude for this object (lat must also be given and representation must be None).

latAngle, optional, must be keyword

The ecliptic latitude for this object (lon must also be given and representation must be None).

distanceQuantity, optional, must be keyword

The distance for this object from the sun’s center. (representation must be None).

pm_lon_coslatAngle, 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_latAngle, optional, must be keyword

The proper motion in the ecliptic latitude for this object (pm_lon_coslat must also be given).

radial_velocityQuantity, optional, must be keyword

The radial velocity of this object.

representation_typeBaseRepresentation 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_typeBaseDifferential 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.

copybool, optional

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

Other Parameters
equinoxTime, 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.

obstimeTime, optional

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

Attributes Summary

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 = 'heliocentricmeanecliptic'
obstime = <Time object: scale='tt' format='jyear_str' value=J2000.000>