computing precession with the HP Prime

[cdeaglejr]

Precession is the slow drift of the Earth’s rotational axis due mainly to the gravitational attraction of the Sun and Moon. The precession matrix transforms coordinates referred to the mean Earth equator and equinox of J2000 to coordinates measured with respect to the mean Earth equator and equinox of date. The precession algorithm used in this HP PPL program is based on the method described in “Expressions for IAU 2000 Precession Quantities”, by N. Capitaine, P. T. Wallace, and J. Chapront, Astronomy and Astrophysics, 412, 567-586 (2003).

The software and documentation for this program can be downloaded from

https://www.dropbox.com/s/6g5t5pu1bhdt1t...s.zip?dl=0