Regiomontanus Y (Moon)

Satellite Feature of Regiomontanus

Named after Muller, Johann Regiomontanus - German astronomer, mathematician (1436-1476).

Regiomontanus is an ancient lunar impact crater located in the southern highlands region to the southeast of Mare Nubium. It is joined at the chaotic northern rim by the crater Purbach, and to the south-southeast is Walther. (wikipedia entry)