Geological Chronicle
Kopff lies along the eastern edge of the inner Mare Orientale impact basin, situated on the western limb of the Moon. From Earth, observers see the crater on edge, where libration influences visibility and orbital vantage is required to discern fine detail.
Investigators once considered Kopff a volcanic structure, but it is more likely an impact crater formed against a surface that was still partly molten. This collision left a sharp-edged, circular rim around a flat, dark interior floor whose albedo matches the lunar mare to the west.
The floor along the northwest and northeast edges is more rugged, escaping the lava that covered the remainder of the basin floor. An infrared spectrum of pure crystalline plagioclase has been detected on the northeast floor, while the southeast section is fractured by narrow rilles.
The International Astronomical Union formally adopted the designation in 1970, honoring German astronomer August Kopff.