Lunar Physical Libration Theory

Like many problems of dynamical astronomy, the integration of the three Euler dynamical equations, which describe the forced physical librations of the Moon, is a very onerous task. The differential equations are complicated, mutually coupled and non-linear. The elaborate numerical treatment of HAYN (1902) furnished solutions which remain authoritative to this day except for the modifications of KOZIEl (1948) who replaced Hansen’s lunar theory with Brown’s theory.