galpy.orbit.Orbit.phi1¶

Orbit.phi1(*args, **kwargs)[source]¶

Return the longitude in a custom sky frame (in deg).

Parameters:

t (numeric, numpy.ndarray or Quantity, optional) – Time at which to get phi1. 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 of observer (in kpc, arranged as [X,Y,Z]; default=object-wide default).
ro (float or Quantity, optional) – Physical scale in kpc for distances 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:

Longitude in the custom sky frame in degrees.

Return type:

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

Notes