Tycho (/ˈtaɪkoʊ/) is a prominent lunar impact crater located in the southern lunar highlands, named after the Danish astronomer Tycho Brahe (1546–1601). It is estimated to be 108 million years old. To the south of Tycho is the crater Street, to the east is Pictet, and to the north-northeast is Sasserides. The surface around Tycho is replete with craters of various sizes, many overlapping still older craters. Some of the smaller craters are secondary craters formed from larger chunks of ejecta from Tycho.It is one of the Moon's brightest craters, with a diameter of 85 km (53 mi) and a depth of 4,800 m (15,700 ft).