apply_proper_motion

rubin_sim.utils.apply_proper_motion(ra, dec, pm_ra, pm_dec, parallax, v_rad, epoch=2000.0, mjd=None)

Applies proper motion between two epochs.

units: ra (degrees), dec (degrees), pm_ra (arcsec/year), pm_dec (arcsec/year), parallax (arcsec), v_rad (km/sec, positive if receding), epoch (Julian years)

Returns corrected ra and dec (in radians)

The function palpy.pm does not work properly if the parallax is below 0.00045 arcseconds

@param [in] ra in degrees. Can be a number or a numpy array (not a list).

@param [in] dec in degrees. Can be a number or a numpy array (not a list).

@param [in] pm_ra is ra proper motion multiplied by cos(Dec) in arcsec/year. Can be a number or a numpy array (not a list).

@param [in] pm_dec is dec proper motion in arcsec/year. Can be a number or a numpy array (not a list).

@param [in] parallax in arcsec. Can be a number or a numpy array (not a list).

@param [in] v_rad is radial velocity in km/sec (positive if the object is receding). Can be a number or a numpy array (not a list).

@param [in] epoch is epoch in Julian years (default: 2000.0)

@param [in] mjd is an instantiation of the ModifiedJulianDate class representing the date of the observation

@param [out] a 2-D numpy array in which the first row is the RA corrected for proper motion and the second row is the Dec corrected for proper motion (both in degrees)