Because of the Ptolemaeus-Alphonsus-Arzachel trio on the west side and the Theophilus-Cyrillus-Catharina trio on the east side, this whole area gets overlooked by many observers. Besides being the just south of the Apollo 16 landing (one of the most difficult sites to locate) it contains a profusion of interesting craters and features. The large craggy crater on the left is Albategnius (139km dia.) with Klein (46km) sitting on its southwest wall. Due south of this is the large ruined crater Parrot (121km). Then east of this crater is a curious looking double crater with a valley cutting through the pair. The lower crater is Vogel (27km) and the upper one is the satellite crater Vogel B and the valley is an illusion crated by two smaller craters that were formed from separate impacts on the northern wall of the “B” crater and the southern wall of Vogel that just happend to be aligned with the centers of the other craters! Moving further south of these we see two craters Argelander (36km) and Airy (37km).
There are four large craters forming an eye catching north-south arc in the center of this image. The top one is Abulfeda (65km), below it is Almanon (51km), then Geber (46km) and lastly the doublet Abeneza (43km) and Azophi (49km). If you are going to this area find these first and use them as your guide to the rest of the area. Due east of Almanon is the crater Tacitus (41km). Notice the line of small craters between these last two running from the bottom of Abulfeda out past Tacitus. This is a catena a controversial latin name for what we used to just call “crater chains”. In this case this is officially Catena Abulfeda. There are several hypothesized origins of these. One is that they are just chance alignments of ejecta from a lager impact that laid down secondary craters in a row. There are a few candidate craters for the origin of such material here. Second would be the volcanic hypothesis that these would be a line of vents along a fault. Third is that a series of impacts from a fragmented asteroid or comet pieces, similar in nature to what we saw with SL9 on Jupiter, but with the moons much lower rotational velocity they are much closer together. In this case a look at the LROC QuickMap image of this crater chain makes the first hypothesis more likely. Go to QuickMap and take a look. What do you think?
