Proceedings of the Celestial Mechanics Conference: Accuracy of the Solar Ephemeris

. A numerical step-by-step integration of the motion of the earth-moon system when compared with New- comb's Tables of the sun shows that the obliquity of the ecliptic is diminishing faster than indicated by Newcomb's theory. Analysis of the differences in longitude, latitude and radius vector indicates that Newcomb's inadequate treat- ment of the squares and products of the disturbing forces has evidently produced important errors in his theory, which is not sufficiently precise for present requirements.