# HeliocentricEclipticIAU76¶

class astropy.coordinates.HeliocentricEclipticIAU76(*args, copy=True, representation_type=None, differential_type=None, **kwargs)[source]

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}

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 sun’s center. (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. 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. copy : bool, optional If True (default), make copies of the input coordinate arrays. Can only be passed in as a keyword argument.

Attributes Summary

Attributes Documentation

default_differential
default_representation
frame_attributes = {'obstime': <astropy.coordinates.attributes.TimeAttribute object>}
frame_specific_representation_info
name = 'heliocentriceclipticiau76'
obstime = <Time object: scale='tt' format='jyear_str' value=J2000.000>