Jet Propulsion Laboratory Developmental Ephemeris
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The Jet Propulsion Laboratory Developmental Ephemeris (JPL DE) is a product of the Jet Propulsion Laboratory in Pasadena, California. This ephemeris is a system of numerical coefficients (for Chebyshev polynomials) which can be used to calculate the positions of the major and some minor planets of the solar system both in the past and the future. The positions given by the calculations represent a "best fit" between the gravitational equations of motion and various observations: distances to planets measured by radio signals from spacecraft, astronomical observations of planets and small bodies in the solar system, and ancient records of eclipses, among others.
There are several different versions of the JPL DE, each one with a 3-digit serial number following. They differ according to the year the data was revised and released, and according to the accuracy and time-range that each JPL DE covers.
[edit] References
- Standish, E.M. & Williams, J.G., “Orbital Ephemerides of the Sun, Moon, and Planets”, in Seidelmann, P. Kenneth, Explanatory Supplement to the Astronomical Almanac (1 ed.), Mill Valley, CA: University Science Books, pp. 279-323, ISBN 0-935702-68-7, <http://www.uscibooks.com/seid.htm>.
- JPL Interoffice Memoranda regarding the ephemerides.
[edit] External links
- JPL FTP site with ephemerides, source code, and documentation.
