CIRS

class astropy.coordinates.CIRS(*args, copy=True, representation_type=None, differential_type=None, **kwargs)[source] [edit on github]

Bases: astropy.coordinates.BaseRADecFrame

A coordinate or frame in the Celestial Intermediate Reference System (CIRS).

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).

ra : Angle, optional, must be keyword

The RA for this object (dec must also be given and representation must be None).

dec : Angle, optional, must be keyword

The Declination for this object (ra must also be given and representation must be None).

distance : Quantity, optional, must be keyword

The Distance for this object along the line-of-sight. (representation must be None).

pm_ra_cosdec : Quantity, optional, must be keyword

The proper motion in Right Ascension (including the cos(dec) factor) for this object (pm_dec must also be given).

pm_dec : Quantity, optional, must be keyword

The proper motion in Declination for this object (pm_ra_cosdec 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.

Other Parameters:
 
obstime : Time

The time at which the observation is taken. Used for determining the position of the Earth and its precession.

Attributes Summary

default_differential
default_representation
frame_attributes
frame_specific_representation_info
name
obstime

Attributes Documentation

default_differential
default_representation
frame_attributes = {'obstime': <astropy.coordinates.attributes.TimeAttribute object at 0x7f7ffef46518>}
frame_specific_representation_info
name = 'cirs'
obstime = <Time object: scale='utc' format='jyear_str' value=J2000.000>