galpy.util.coords.pmllpmbb_to_pmrapmdec(pmll, pmbb, l, b, degree=False, epoch=2000.0)[source]

Rotate proper motions in (l,b) into proper motions in (ra,dec)

  • pmll (float or numpy.ndarray) – Proper motion in l (multiplied with cos(b)) (mas/yr)

  • pmbb (float or numpy.ndarray) – Proper motion in b (mas/yr)

  • l (float or numpy.ndarray) – Galactic longitude

  • b (float or numpy.ndarray) – Galactic latitude

  • degree (bool, optional) – If True, l and b are given in degrees (default=False)

  • epoch (float, optional) – Epoch of ra,dec (right now only 2000.0 and 1950.0 are supported when not using astropy’s transformations internally; when internally using astropy’s coordinate transformations, epoch can be None for ICRS, ‘JXXXX’ for FK5, and ‘BXXXX’ for FK4)


[pmra x cos(dec),pmdec] in (mas/yr,mas/yr). For vector inputs [:,2]

Return type:

tuple or numpy.ndarray


  • 2010-04-07 - Written - Bovy (NYU)

  • 2014-06-14 - Re-written w/ numpy functions for speed and w/ decorators for beauty - Bovy (IAS)