Brown’s Lunar Treatise: Theory of the Motion of the Moon; Containing a New Calculation of the Expressions for the Coordinates of the Moon in Terms of the Time

Abstract

This treatise, published in Volumes 53, 54, 57, and 59 of the Memoirs of the Royal Astronomical Society (1897–1908), embodies some 18 years of calculative labor,from 1890 to 1907, on the development of the lunar theory. Initially Brown worked alone, but after 1895 he was assisted by Ira I. Sterner, A.B., of Haverford College, as a computer. The treatise incorporated the results of Brown’s earlier papers, and carried to completion the task he had set for himself. This consisted of two sub-tasks. In the first and more extensive of these, he developed the theory under idealizing restrictions: the assumption of a strictly elliptical orbit for the Sun relative to the center of gravity of the Earth and Moon, and the representation of the bodies of the Moon, Earth, and Sun as point-masses – equivalent to assuming the mass-distribution within each of them to be spherically symmetrical.