Calculate the approximate geocentric position of the Moon using a full implementation of the algorithm published by Meeus (l’ Astronomie, June 1984, p348).

void palDmoon( double date, double pv[6] );

date = double (Given)

pv = double [6] (Returned)

• Meeus quotes accuracies of 10 arcsec in longitude, 3 arcsec in latitude and 0.2 arcsec in HP (equivalent to about 20 km in distance). Comparison with JPL DE200 over the interval 1960-2025 gives RMS errors of 3.7 arcsec and 83 mas/hour in longitude, 2.3 arcsec and 48 mas/hour in latitude, 11 km and 81 mm/s in distance. The maximum errors over the same interval are 18 arcsec and 0.50 arcsec/hour in longitude, 11 arcsec and 0.24 arcsec/hour in latitude, 40 km and 0.29 m/s in distance.

• The original algorithm is expressed in terms of the obsolete timescale Ephemeris Time. Either TDB or TT can be used, but not UT without incurring significant errors (30 arcsec at the present time) due to the Moon’ s 0.5 arcsec/sec movement.

• The algorithm is based on pre IAU 1976 standards. However, the result has been moved onto the new (FK5) equinox, an adjustment which is in any case much smaller than the intrinsic accuracy of the procedure.

• Velocity is obtained by a complete analytical differentiation of the Meeus model.