Theophilus (Moon)

Named after Theophilus - Greek astronomer (unkn-A.D. 412).

Theophilus is a prominent lunar impact crater that lies. To the east is the smaller crater Mädler and further to the south-southeast is Beaumont. Theophilus, Cyrillus and Catharina form a prominent group of large craters visible on the terminator 5 days after the new moon. (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.