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)