Wikipedia
Dirichlet (crater)
Dirichlet is a lunar impact crater that is located on the Moon's far side. It is attached to the southern outer rim of the crater Henyey. To the south-southeast is the much larger crater Tsander.
This is a circular crater with a sharp-edged rim that is not significantly worn. There are slight outward protrusions along the eastern side. The sides of the inner walls have slumped down to form a ring of scree along the base.
Dirichlet lies on the eastern margin of the Dirichlet-Jackson Basin.