galpy.orbit.Orbit.pmphi1¶

Orbit.pmphi1(*args, **kwargs)[source]¶

Return proper motion in custom-frame longitude (in mas/yr, includes cos(phi2)).

Parameters:

t (numeric, numpy.ndarray or Quantity, optional) – Time at which to get pmphi1. Default is the initial time.
T (numpy.ndarray, optional) – 3x3 rotation matrix from (ra, dec) to (phi1, phi2). Default is the matrix stored by a previous call to align_to_orbit(). Required if no such call was made.
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).
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 phi1 in mas/yr.

Return type:

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

Notes