Blancanus is a lunar impact crater located in the rugged southern region of the Moon, to the southwest of the walled plain Clavius. To the northwest lies the comparably sized crater Scheiner, and south-southwest of Blancanus is the worn Klaproth.

Clavius is one of the largest crater formations on the Moon and the second largest crater on the visible near side. It is located in the rugged southern highlands of the Moon, to the south of the prominent ray crater Tycho. It is named for the Jesuit priest Christopher Clavius.