Geological Chronicle
Doppelmayer is the basalt-flooded remnant of an impact crater spanning 65.08 kilometers in diameter on the southwest edge of Mare Humorum. Formed during the Nectarian epoch, the structure sits in a region crowded with drowned terrain, including the flooded crater Lee to the south-southeast and the nearly submerged crater Puiseux to the east-northeast. Erosion and ancient volcanic flooding have worn down its circular outline, leaving the southwest rim as its most prominent section while the northeast rim sinks beneath the mare surface as a gentle rise.
The crater interior preserves clear evidence of partial basalt inundation. A prominent raised ridge rises near the center of the flooded floor, with a small range of hills curving west and north from its southern tip in a pattern nearly concentric with the outer rim. Across sections of the floor uncovered by lava, the ground is fractured into networks of cracks. Beyond the crater's western flank lie the slender rilles of Rimae Doppelmayer, narrow fissures that require steady atmospheric seeing and an aperture of at least 150 millimeters to resolve through a telescope.
The crater honors Johann Gabriel Doppelmayr, an 18th-century German mathematician and astronomer. German observer Johann Hieronymus Schröter originally introduced the name to lunar maps, and the International Astronomical Union formally adopted the designation in 1935.