Photographic Techniques for the Determination of the Moon’s Constants of Rotation

Abstract

To date all primary selenodetic results rest upon heliometer measures. The heliometer can be replaced by the long focus photographic refractor, provided that the problems of scale and orientation can be surmounted. The paper outlines the use of ordinary and sinusoidal star trails for the solution of these problems. The analysis of the measures can follow that of classical selenodesy, involving the lunar limb, but the lunar photograph permits a better approach. In this no reference is made to the limb and the weakness of the classical method, that is, the vagueness of the center of figure, is avoided. Instead the selenodetic coordinates are referred to a visible point on the lunar surface as origin.

Research supported by the Air Force Cambridge Research Laboratories , U.S. Air Force , under Contract AF 19(628)-4332.