Differences in the Moon’s moments of inertia

The constants of the Moon’s physical libration constitute the selenodesic basis for lunar cartography. The author worked out a new method for a simultaneous determination of these constants from heliometric observations of the Moon and applied it to four heliometric series comprising 3282 observations covering the period 1877–1915, and performed a joint adjust­ment of these series by eliminating the Moon’s mean radius corresponding to each series, as it might be affected by the effect of irradiation. At the same time the author gave an exact proof for the uniqueness of the solution for the mechanical ellipticity of the Moon f which turned out to lie below the critical value 0∙662, thus enabling an accurate determina­tion of the differences of the Moon’s moments of inertia.