Thiessen (Moon)

Named after Georg Heinrich Thiessen - German astronomer (1914-1961).

Thiessen is a lunar impact crater that lies in the far northern latitudes, on the far side. To the west is the younger crater Ricco, and to the south-southwest is Roberts. Farther to the east lies Heymans. This is a heavily worn crater with overlapping impacts along the rim to the northeast, northwest, and west. (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.