Named after Erasmus Reinhold - German astronomer, mathematician (1511-1553).
Reinhold is a prominent lunar impact crater that lies to the south-southwest of the crater Copernicus, on the Mare Insularum. The interior walls are terraced and the irregular outer ramparts are visible against the flat surface of the mare. The interior floor is featureless, with only a few low rises. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On the Moon they are named after deceased scientists, polar explorers, astronauts or cosmonauts.
