The floor of Clavius crater is littered with smaller impact crater. The largest is Rutherfurd at the end of curving chain of ever diminishing craters. From largest to smallest, these craters are designated Clavius D, C, N, J, and JA. This sequence of diminishing craters has proved a useful tool for amateur astronomers that want to test the resolution of their small telescopes.
Clavius is one of the largest crater formations on the Moon, and it is the third 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.