Alphonsus (71 miles) is directly south of Ptolemaeus and its northern wall abuts on Ptolemaeus’ southern wall. Its walls are 1½ miles above the large flat floor. There is a small, but prominent central peak that is a little over a ½ mile high. The floor has some dark regions; the largest is on the western floor. The eastern floor has an extensive system of rills. This formation is a must show for yourself and your guests at first quarter.
Arzachel (59 miles) is the third of three great craters in a north-south alignment. Ptolemaeus and Alphonsus are its big brothers, but is no slouch itself. It is the deepest of the three with terraced walls that tower over 2 miles about its flat floor. There is a rill system on the eastern floor and an elongated central mountain mass that is over ½ mile high. The floor is rough with hills and small craters. The crater due east of the central mountain is 6 miles across and about a mile deep.