Semi-Analytical Lunar Ephemeris - the Main Problem

Extract

The theory of the motion of the Moon can be approached by two types of methods. In the analytical methods, the solution is usually expanded in formal power series of the small quantities m, e and γ. It is known that the expansions in m are slowly convergent and that, in order to obtain an accuracy of the order of the meter, the expansions have to be carried to very high order (beyond 20) involving several hundred thousands terms.