ELP 200085: a semianalytical lunar ephemeris adequate for historical times
Abstract
New expressions for mean lunar arguments are obtained. With respect to ELP 200082, the main improvement consists in computing secular terms proportional to powers 3 and 4 of time. Such terms arise from secular variations of solar eccentricity and longitude of perigee, Earth figure effects and tidal effects. A semianalytical solution for the lunar motion, ELP 200085, is presented which is valid over a time span of few thousand years and easily handled. Its estimated internal precision varies from 0".5 to about 10" over the time span (2000A.D.  1500B.C.). A comparison of ELP 200085 with the JPL numerical integration LE 51, over a similar time span, has been performed. The leading point of the comparison is a secular drift of 0".0351/cy^{2} in mean mean longitude between the two solutions. After removing this secular drift the differences have the same magnitude as the estimated internal precision of ELP 200085. For historical times, this secular drift as well as internal uncertainty of ELP 200085 are far below the uncertainties resulting from the tidal secular acceleration. For practical purpose, we give in an appendix, an abridged solution usable to compute a low precision lunar ephemeris (20") over a long time span for a given value of the tidal secular acceleration (23".895/cy^{2}).
 Publication:

Astronomy and Astrophysics
 Pub Date:
 January 1988
 Bibcode:
 1988A&A...190..342C
 Keywords:

 Celestial Mechanics;
 Moon;
 Planet Ephemerides;
 Secular Variations;
 Tides;
 MOON;
 EPHEMERIDES;
 HISTORY;
 CELESTIAL MECHANICS;
 ASTRONOMY;
 MODELS;
 ANALYTICAL METHODS;
 CALCULATIONS;
 MOTION;
 COMPARISONS;
 TIDAL EFFECTS;
 STABILITY;
 PARAMETERS;
 ECCENTRICITY;
 COMPTER METHODS;
 Astronomy; Moon