  Leonhard Euler, the most prolific mathematician in history, contributed to
advance a wide spectrum of topics in celestial mechanics. At the Saint
Petersburg Observatory, Euler observed sunspots and tracked the movements of
the Moon. Combining astronomical observations with his own mathematical genius,
he determined the orbits of planets and comets. Euler laid the foundations of
the methods of planetary perturbations and solved many of the Newtonian
mechanics problems of the eighteenth century that are relevant today. In his
study of the three-body problem, Euler discovered two of the five equilibrium
points so-called the Lagrangian points. His pioneering work in astronomy was
recognized with six of the twelve prizes he won from the Paris Academy of
Sciences. In this article, we review some of Euler's most interesting
contributions to astronomy.
