DE400

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DE400 (DE403, DE405, DE406, etc) is a series of software packages that provide a means of generating the JPL Planetary and Lunar Ephemerides [1].

These ephemerides calculate the rectangular co-ordinates of the Sun, Moon, and nine major planets, with respect to the International Celestial Reference Frame.

Each package includes a set of data files and a few Fortran routines which can interpolate the planetary and lunar co-ordinates to high precision. DE405 accuracy for the inner planets is about 0.001 arcseconds (equivalent to about 1 km at the distance of Mars); for the outer planets it is generally about 0.1 arcseconds. The 'reduced accuracy' DE406 ephemeris gives an interpolating accuracy (relative to the full ephemeris values) no worse than 25 metres for any planet and no worse than 1 metre for the moon.

Documentation for later JPL ephemerides has hinted that C and Java versions of the interpolating routines will be supported in future packages.

Nevertheless, the software is not intended for a casual user. It is available for download by anonymous FTP from ftp://ssd.jpl.nasa.gov/pub/eph/export