Stefan is a lunarimpact crater on the far side of the Moon, just beyond the northwestern limb. Attached to the western rim is the slightly smaller crater Wegener, and close to the eastern rim is Rynin.
As with many craters of this size on the Moon, the outer rim has been worn by impact erosion and the edge and inner wall are generally pitted with small craterlets. The southern edge of the rim in particular has been damaged by impacts, and is overlain by the satellite crater Stefan L. This bowl-shaped crater lies at the center of a small ray system, which is indicative of a relatively young impact.
The interior floor of Stefan is a generally level surface that is marked by several impacts. The most notable is a ring-shaped crater rim projecting up through the southern half of the floor. Near the midpoint is a low hill, possibly the buried remnant of a central peak.
Prior to formal naming by the IAU in 1970,[1] Stefan was called Crater 100.[2]
Menzel, D. H.; Minnaert, M.; Levin, B.; Dollfus, A.; Bell, B. (1971). "Report on Lunar Nomenclature by the Working Group of Commission 17 of the IAU". Space Science Reviews. 12 (2): 136–186. Bibcode:1971SSRv...12..136M. doi:10.1007/BF00171763. S2CID122125855.