Seeliger is a relatively small lunar impact crater that lies near the southeastern edge of Sinus Medii. It was named after the German astronomer Hugo von Seeliger. This is a circular, cup-shaped feature that has not been appreciably worn by impact erosion. To the southeast is a rille named the Rima Réaumur, following a line to the northwest. In the north is the 110-km-long Rima Oppolzer, which divides the mare where Seeliger is situated from the remainder of the Sinus Medii. Satellite craters By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Seeliger. References External links Seeliger at The Moon Wiki Impact craters on the Moon