galpy.orbit.Orbit.pmra¶

Orbit.pmra(*args, **kwargs)[source]¶

Return proper motion in right ascension (in mas/yr).

Parameters:

t (numeric, numpy.ndarray or Quantity, optional) – Time at which to get the proper motion. Default is the initial time.
obs (numpy.ndarray, Quantity or Orbit, optional) – Position and velocity of observer (in kpc and km/s, arranged as [X,Y,Z,vx,vy,vz]; default=object-wide default) OR Orbit object that corresponds to the orbit of the observer. Note that when Y is non-zero, the coordinate system is rotated around z such that Y’=0.
ro (float or Quantity, optional) – Physical scale in kpc for distances to use to convert. Default is object-wide default.
vo (float or Quantity, optional) – Physical scale for velocities in km/s to use to convert. Default is object-wide default.
use_physical (bool, optional) – Use to override object-wide default for using a physical scale for output.
quantity (bool, optional) – If True, return an Astropy Quantity object. Default from configuration file.

Returns:

Proper motion in right ascension in mas/yr.

Return type:

float, numpy.ndarray or Quantity [*input_shape,nt]

Notes