Firmicus (Moon)

Named after Julius Maternus of Syracuse Firmicus - Roman astrologer (fl. A.D. 330-354).

Firmicus is a lunar crater that lies in the eastern part 's near side, so that from Earth it appears oval in shape due to foreshortening. It is, however, very nearly circular. The crater is located to the west of the Mare Undarum, and northeast of the similar-sized crater Apollonius. To the north are the craters van Albada and Auzout. (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.