Commission 4: Ephemerides

Extract

JPL continues to be active in creating ephemerides in support of spacecraft navigation as well as various other functions. Many of the products are available on web sites: (a) “Horizons”, the interactive web site, updated on an hourly basis, is located at http://ssd.jpl.nasa.gov. As of August, 2005, it contains orbital elements and ephemerides for the sun and 9 planets, 150 natural satellites (including the Moon), 291, 655 asteroids, 1631 comets, and 34 Spacecraft. Horizons uses the full precision of the JPL DE405.

(b)JPL's Planetary and Lunar Ephemerides in “export” format are available via FTP from the Internet: ftp://ssd.jpl.nasa.gov/pub/eph/export/ or on a CD-ROM: http://www.willbell.com/software/jpl.htm We advise to read the attached README.

(c)The observational data used in fitting the planetary ephemerides is available at the following web site, updated periodically: http://ssd.jpl.nasa.gov/plan-eph-data/

(d)SPICE Toolkit is a subroutine package for experienced programmers who write their own main driving programs for astrometrical computations. SPICE is available at http://naif.jpl.nasa.gov/. It contains a large library of subroutines useful in reading SPICE format ephemeris files (SPK) and in computing many solar system observation geometry parameters associated with the various JPL solar system missions. Available in Fortran, C, and IDL for most popular computing platforms.