Geological Chronicle
West crater is a small crater spanning 0.19 kilometers across in Mare Tranquillitatis on the Moon, east of the Apollo 11 landing site known as Tranquility Base. The feature served as a major landmark during the lunar descent on July 20, 1969. The International Astronomical Union formally adopted the name in 1973.
During the descent of the Lunar Module Eagle, astronauts Neil Armstrong and Buzz Aldrin flew over West crater at an altitude of about 100 meters. Armstrong saw a need to avoid the crater's boulder field ejecta, as well as Little West crater just beyond it, before landing Eagle approximately 550 meters west of West crater.
The name reflects an earlier convention where lunar directions were described from the perspective of an observer on Earth. The feature was called West Crater under that framing, even though it appears east of the landing site on modern lunar maps.