Apollonius (Moon)

Named after Apollonius of Perga - Greek mathematician (c. 262-190 B.C.).

Apollonius is a lunar crater located near the eastern limb. It lies in the region of uplands to the west of Mare Undarum and northeast of the Sinus Successus on the Mare Fecunditatis. It is southwest of the crater Firmicus, and north of Condon. The outer rim is somewhat worn and is overlain by a pair of small craters across the western wall. (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.