Geological Chronicle
Located in the southern hemisphere on the Moon's far side, Finsen spans 72.98 kilometers in diameter along the southeastern exterior of the walled plain Leibnitz. Ejecta from Finsen covers the southeastern part of the interior floor of Leibnitz, with another walled plain, Von Kármán, lying to the southwest. The crater honors Niels Ryberg Finsen, the Danish phototherapist and Nobel laureate.
The formation dates to the Eratosthenian epoch of the lunar geologic timescale, remaining relatively young with well-defined features that have not been significantly eroded by subsequent impacts. Its rim is circular but uneven, showing outward protrusions along all sides except to the north and northwest. Slumping along the inner wall produces a sharp rim edge in the southern half alongside short terraces.
Because the inner wall is wider to the north, the relatively level interior floor is offset slightly to the south. At the midpoint rises a central peak occupying roughly 15 kilometers with a higher albedo than the surrounding floor or rim. Spectra of this orthopyroxene-rich peak fit a gabbroic norite mineralogy that originated from a depth of 7.2 to 11.2 kilometers.