Use of this function is appropriate when efficiency is important and where many star positions, all with parallax and proper motion either zero or already allowed for, and 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 function.

The corresponding function for the case of non-zero parallax and proper motion is palMapqk.

rm = double (Given)

dm = double (Given)

amprms = double[21] (Given)

ra = double $\ast$ (Returned)

da = double $\ast$ (Returned)

• The reference systems and timescales used are 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).

• The vector amprms(4-6) is referred to the mean equinox and equator of epoch 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.