# galpy.orbit.Orbit.ll¶

Orbit.ll(*args, **kwargs)[source]

NAME:

ll

PURPOSE:

return Galactic longitude

INPUT:

t - (optional) time at which to get ll

obs=[X,Y,Z] - (optional) position of observer (in kpc)
(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)

OUTPUT:

l(t) [*input_shape,nt]

HISTORY:

2019-02-21 - Written - Bovy (UofT)