The Overlap Approach toward the Derivation of Photographic Stellar Coordinates

Abstract

The use of the conditions imposed by the appearance of one star on more than one photographic plate to strengthen the determination of the relationship between the measurement coordinate systems and the system of celestial right ascension and declination, was first advocated by Eichhorn (1960), and since then various reduction procedures have been proposed to incorporate these conditions in the plate-reduction process (Eichhorn, 1963; Henriksen, 1964; Lacroute, 1964; Googe, 1967; Clube, 1967). During the last several years at the Army Map Service the overlap method has been developed and used in several astrometric projects, and the purpose of this paper is to summarize the main features of the algorithm and some of the projects to which it has been applied.