calculate_apparent_motion

lsst.drp.tasks.gbdesAstrometricFit.calculate_apparent_motion(catalog, refEpoch)

Calculate shift from reference epoch to the apparent observed position at another date.

This function calculates the shift due to proper motion combined with the apparent motion due to parallax. This is not used in the GbdesAstrometricFitTask or related child tasks, but is useful for assessing results.

Parameters:

catalogastropy.table.Table

Table containing position, proper motion, parallax, and epoch for each source, labeled by columns ‘ra’, ‘dec’, ‘pmRA’, ‘pmDec’, ‘parallax’, and ‘MJD’.

refEpochastropy.time.Time

Epoch of the reference position.

Returns:

apparentMotionRAnp.ndarray [astropy.units.Quantity]

RA shift in degrees.

apparentMotionDecnp.ndarray [astropy.units.Quantity]

Dec shift in degrees.