Table 5-12 for the 12 terms used in SMPOS. The distancé R from the Earth to the Moon is determined from the lunar parallax, P, as

Brown gives a cosine series for P with the same arguments as for SL^. The terms used in SMPOS are given in Table 5-13.

The positions of the planets may be calculated using mean elements for the inner planets and osculating elements for the outer planets. Subroutine PLANET uses elements for December 19, 1974, as given in Appendix L. The positions from PLANET are within 0.02 deg for times within 2 years of the epoch and are within 0.1 deg for times within 6 or 7 years of the epoch. These elements should be updated periodically by consulting a current American Ephemeris.

Table 5-13. Periodic Terms for Calculating the Lunar Parallax
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