Named after Tycho Brahe - Danish astronomer (1546-1601).
Tycho is located in the Cerberus hemisphere of Mars, around 49.8° south and 213.9° west, in an area which is southeast of the Martz crater and east of the Hellas Basin. (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.