Geological Chronicle
Situated beside the Moon's northeastern limb, Hayn spans a diameter of 86.21 kilometers across the northwestern rim of the walled plain Bel'kovich, north of Mare Humboldtianum. This peripheral position limits the amount of detail visible from Earth, leaving the western inner slope permanently hidden from sight. Observation is also subject to lunar libration, which can completely conceal the crater. Relatively isolated from other named craters, Hayn's nearest neighbor is Cusanus to the northwest.
Hayn is a young crater whose rim and interior have not yet been significantly eroded. It has a circular but somewhat uneven rim and an inner wall lined with terraces, accompanied by an outer rampart that is most extensive to the southwest. The southern rim is more pronounced in height where it joins the heavily worn rim of Bel'kovich. To the east of Hayn, little trace of Bel'kovich's rim remains, blending into the surrounding terrain. Because the crater possesses a ray system, it is mapped as part of the Copernican System.
The interior floor is relatively flat compared with the surrounding terrain. Near the midpoint lies a system of several ridges divided in two by a wide north-south valley, flanked by smaller lateral valleys that yield roughly half a dozen peaks in total. Several smaller hills dot the remainder of the floor, particularly to the west of the central range. In addition, the infrared spectrum of pure crystalline plagioclase has been identified on this central peak.