A Study of the Figure of the Moon from Photographs of the Full Moon

A study of the general figure of the Moon is of great importance for the solution of many problems. First of all, in astrometric observations of the Moon the position of its centre is determined by reference to its limb; and thus in order to compare the observed coordinates of the Moon with ephemerides it is necessary to adopt a definite hypothesis about the form of the limb. On the other hand, when compiling maps of the marginal zone of the Moon it is necessary to refer the heights of individual points to the barycentric sphere, common for all sections of the limb and all phases of libration. And, thirdly, studies of the rotation of the Moon and of its physical librations are also connected with the measurement of points on the limb and require the knowledge of its general form. Finally, a knowledge of the exact figure of the Moon is highly important for the theory of the origin and evolution of our satellite.