Maskelyne (Moon)

Named after Nevil Maskelyne - British astronomer (1732-1811).

Maskelyne is a solitary lunar crater that lies in the southeast part of the Mare Tranquillitatis. The outer rim has a somewhat polygonal shape, although it is generally circular. The inner walls are terraced and there is a low central rise at the midpoint of the floor. The landing site of the Apollo 11 expedition is located about 250 kilometers to the west-southwest. (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.