Geological Chronicle
Sulpicius Gallus is a small, bowl-shaped impact crater measuring 11.61 kilometers across near the southwestern edge of Mare Serenitatis. About 10 kilometers to the south and east rises the Montes Haemus range, which forms the edge of the Serenitatis basin. The feature takes its name from Gaius Sulpicius Gallus, a Roman astronomer active in the second century BC.
The crater exhibits a relatively high albedo and a sharp-edged rim showing little appearance of wear. A small rise occupies the midpoint, and orange-colored material was observed across recent highland deposits within the interior by Apollo 17 astronauts during their lunar module ascent.
To the northwest lies a rille system designated Rimae Sulpicius Gallus, which extends for a distance of about 90 kilometers. These rilles branch and curve outward as they track the southwestern edge of the lunar mare.