In 1693 G. D. Cassini published the three following empirical laws on the Moon’s rotational motion: (1) The Moon rotates uniformly about its polar axis with a rotational period equal to the mean sidereal period of its orbit about the earth. (2) The inclination of the Moon’s equator to the ecliptic is a constant angle approximately 1°5. (3) The ascending node of the lunar orbit on the ecliptic coincides with the descending node of the lunar equator on the ecliptic.