Van Vleck (Moon)

Named after John Monroe Vleck - American astronomer, mathematician (1833-1912).

Van Vleck is a lunar impact crater that is located near the northeastern rim of the walled plain Gilbert, to the west of the Mare Smythii. The similar crater Weierstrass is nearly joined to the northwestern rim. To the east is the small Carrillo. The rim of this crater is nearly circular with no overlying craters of note, although a small crater abuts against the northeastern side and another along the southern inner 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.