Quick mean to apparent place: transform a star RA,Dec from mean place to geocentric apparent place, given the star-independent parameters.

Use of this routine is appropriate when efficiency is important and where many star positions, all referred to the same equator and equinox, are to be transformed for one epoch. The star-independent parameters can be obtained by calling the palMappa routine.

If the parallax and proper motions are zero the palMapqkz routine can be used instead.

void palMapqk ( double rm, double dm, double pr, double pd, double px, double rv, double amprms[21], double $\ast$ra, double $\ast$da );

rm = double (Given)

dm = double (Given)

pr = double (Given)

pd = double (Given)

px = double (Given)

rv = double (Given)

amprms = double [21] (Given)

ra = double $\ast$ (Returned)

dec = double $\ast$ (Returned)

• The reference frames and timescales used are post IAU 2006.

• The mean place rm, dm and the vectors amprms[1-3] and amprms[4-6] are referred to the mean equinox and equator of the epoch specified when generating the precession/nutation matrix amprms[12-20]. In the call to palMappa (q.v.) normally used to populate amprms, this epoch is the first argument (eq).

• Strictly speaking, the routine is not valid for solar-system sources, though the error will usually be extremely small. However, to prevent gross errors in the case where the position of the Sun is specified, the gravitational deflection term is restrained within about 920 arcsec of the centre of the Sun’ s disc. The term has a maximum value of about 1.85 arcsec at this radius, and decreases to zero as the centre of the disc is approached.