is a
Lunar Impact Crater in the southeast part of the
Moon . It is located to the south-southeast of the larger
Catharina Crater , in the area framed by the
Rupes Altai scarp. Some distance to the northeast is the
Mare Nectaris , with the
Beaumont and
Fracastorius flooded craters.
The crater rim of Polybius appears slightly distended in the northeast, and has a cut through the northern wall. But the wall is otherwise moderately intact with only minor erosion. The interior floor is flat and almost featureless, with no central rise. To the south and east, a
Ray from the
Crater Tycho cuts across the bowl-shaped 'Polybius A' and 'Polybius B' craterlets.
By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to Polybius crater.
