This old walled plain forms, with Langrenus, Petavius and Furnerius, a line of four similarly-sized craters (very roughly 150km across) centred on the 61°east line of longitude. Its northern end is almost entirely obliterated by the craters Lamé (north east) and Lohse (north west).

Photo: António Cidadão. His Home Page of Astrophotography includes stereograms, animations, and "Seven Craters a Week" from his forthcoming photographic lunar atlas.

Inconstant Moon