A Note on the Evaluation of the Latitude of the Moon

Investigations of a discrepancy of about $$0^{\prime\prime}.034 \,\text{sin} \,(F-2D)$$ between two methods for the evaluation of the fundamental lunar ephemeris have revealed a numerical error in a coefficient used in the reverse transformation by Eckert, Walker and Eckert of Brown's series for the latitude of the Moon. As a consequence, the series given by them for the differential correction of the Improved Lunar Ephemeris requires amendment. The investigations have also shown that the interpretation of Brown's formula for the latitude that was used in the Improved Lunar Ephemeris does not give the best representation of Brown's original series.