Byrgius (crater)

Byrgius

Lunar Orbiter 4 image of Byrgius, with Byrgius A at right, and Byrgius D in upper left
Coordinates	24°42′S 65°18′W / 24.7°S 65.3°W / -24.7; -65.3Coordinates: 24°42′S 65°18′W / 24.7°S 65.3°W / -24.7; -65.3
Diameter	87 km
Depth	4.6 km
Colongitude	65° at sunrise
Eponym	Joost Bürgi

Byrgius is a lunar crater located in the western part of the Moon, near the limb. As a result, Byrgius appears strongly oval in form due to foreshortening. To the northwest is the nearly ruined crater Lamarck. The rim of Byrgius is worn and eroded, with Byrgius A overlying the eastern rim and Byrgius D lying across the northwest. The floor is relatively flat and undistinguished by significant craterlets. Byrgius A possesses its own ray system that extends for over 400 kilometres.

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Byrgius.