pm_icrs_to_gal¶
-
gala.coordinates.
pm_icrs_to_gal
(coordinate, pm)[source]¶ Convert proper motion in ICRS coordinates (RA, Dec) to Galactic coordinates (l,b).
Parameters: coordinate :
SkyCoord
,BaseCoordinateFrame
An instance of an Astropy coordinate object. Can be in any frame that is transformable to ICRS coordinates.
pm :
Quantity
, iterableReturns: pm :
Quantity
An astropy
Quantity
object specifying the proper motion vector array in Galactic coordinates. Will have shape (2,N).Examples
>>> import astropy.units as u >>> import astropy.coordinates as coord >>> c = coord.SkyCoord(ra=196.5*u.degree, dec=-10.33*u.deg, distance=16.2*u.kpc) >>> pm = [-1.84741767, 3.34334366]*u.mas/u.yr >>> pm_icrs_to_gal(c, pm) <Quantity [-1.52999988, 3.49999973] mas / yr>