Sosigenes is a lunar impact crater on the west edge of Mare Tranquillitatis.
[1] It lies to the east of the large walled plain Julius Caesar.
The crater rim has a high albedo, making it relatively bright.
To the east on the mare is a formation of parallel rilles designated the Rimae Sosigenes.
By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Sosigenes.