Astronomical Solutions for Earth Paleoclimates The longest ever solar system calculation (23,000,000 years) is now officially used for geological dating based on Milankovitch cycles. http://www.imcce.fr/Equipes/ASD/insola/earth/earth.html
JPL Horizons The JPL Horizons On-Line Ephemeris System provides easy access to key solar system data and flexible production of highly accurate ephemerides for solar system objects. This includes 170,000+ asteroids & comets, 128 natural satellites, 9 planets, the Sun, select spacecraft, and several dynamical points such as Earth-Sun L1, L2 and system barycenters. http://ssd.jpl.nasa.gov/?horizons_doc
Jean-Pierre Desmoulins pages Sunspot cycles are they caused by Venus, Earth and Jupiter syzygies? Slightly off topic, but he has a program for calculating syzygies between any group of planets. http://perso.wanadoo.fr/jpdesm/sunspots
Lunar Constants and Models Document Very detailed pdf document on the moon and its orbit in relation to the Earth. Even goes into the minor discrepancies of the moon's mass distribution suitable for artificial satellite navigation. http://ssd.jpl.nasa.gov/dat/lunar_cmd_2005_jpl_d32296.pdf
Swiss Ephemeris Programs for calculating planetary ephemeris to good accuracy over a few thousand years. Astrological orientation. http://www.astro.com/swisseph/
