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. One of the rays from
Tycho, when extended across the
Oceanus Procellarum, intersects this crater. This was a factor in the choice of the crater's name when
Giovanni Riccioli was creating his system of
lunar nomenclature, as Kepler used the observations of
Tycho Brahe while devising his three laws of planetary motion. On Riccioli's maps, this crater was named
Keplerus, and the surrounding skirt of higher
albedo terrain was named
Insulara Ventorum. Due to its prominent rays, Kepler is mapped as part of the
Copernican System. File:Kepler crater 3162 med.jpg|Oblique view from
Lunar Orbiter 3 Image:AS12-52-7745.jpg|Kepler from
Apollo 12 File:Aldo Ferruggia - Kepler mineral.jpg|Kepler area with mineral postprocessing (L(DVF)+C -daytime acquisition) ==Satellite craters==