Clavius is the second largest crater on the lunar near side. It's most characteristic feature is the chain of impact craters on it's floor. These craters of different size are a good way to test the resolution of modest telescopes. The northern rim is sharp and shows terrasses. Superimposed on the rim is the 52km crater Porter.
The southern border of Clavius shows some decay already with less sharply defined features. The southern rim is broken by the crater Rutherfurd, which is also the largest crater of the clavius crater chain.
When the sun is still low over the lunar hoorizon the floor of Clavius can still be dark while already illuminating the edges of the chain craters.