galpy.util.coords.radec_to_lb

galpy.util.coords.radec_to_lb(ra, dec, degree=False, epoch=2000.0)[source]

Transform from equatorial coordinates to Galactic coordinates

Parameters:

  • ra (float or numpy.ndarray) – Right ascension

  • dec (float or numpy.ndarray) – Declination

  • degree (bool, optional) – If True, ra and dec are given in degree and l and b will be as well

  • 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)

Returns:

Galactic longitude and latitude

Return type:

tuple or numpy.ndarray

Notes

  • 2009-11-12 - Written - Bovy (NYU)

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

  • 2016-05-13 - Added support for using astropy’s coordinate transformations and for non-standard epochs - Bovy (UofT)