Kepler (Latin Keplerus) is a lunar impact crater that lies between the Oceanus Procellarum to the west and Mare Insularum in the east. To the southeast is the crater Encke. Kepler is most notable for the prominent ray system that covers the surrounding mare. The rays extend for well over 300 kilometers, overlapping the rays from other craters. Kepler has a small rampart of ejecta surrounding the exterior of its high rim. The outer wall is not quite circular, and possesses a slightly polygonal form. The interior walls of Kepler are slumped and slightly terraced, descending to an uneven floor and a minor central rise.