galpy.orbit.Orbit.pmra¶
- Orbit.pmra(*args, **kwargs)[source]¶
NAME:
pmra
PURPOSE:
return proper motion in right ascension (in mas/yr)
INPUT:
t - (optional) time at which to get pmra
- obs=[X,Y,Z,vx,vy,vz] - (optional) position and velocity of observer
(in kpc and km/s) (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= distance in kpc corresponding to R=1. (default=Object-wide default)
vo= velocity in km/s corresponding to v=1. (default=Object-wide default)
OUTPUT:
pm_ra(t) in mas / yr [*input_shape,nt]
HISTORY:
2019-02-21 - Written - Bovy (UofT)