When first observing the moon most amateur astronomers are enamored by the big craters like Copernicus, Tycho or the trio Ptolemaeus, Alphonsus and Alpetrageus. But there are features that are too often overlooked (rather than ‘over-looked’) and three of them are represented here. The most obvious is the the medium sized but beautifully formed Eratosthenes (59km dia.) with its great terraced interior walls surrounded by a hatch-work ejecta blanket. This blanket has splash that extends a full crater diameter from the crater walls. In the lower left of this image can be seen part of one wall of the great crater Copernicus (93km).
The next feature is circle below and to the right of Eratosthenes. This is Stadius, a ghost crater, one of the best on the moon. It is a very old crater obviously predating flooding from more recent impacts like Copernicus and Eratosthenes and the local mare. Scattered from north to south to the left and even on Stadius, are small pits and craterlets from 1-6km in size. These are secondary craters created from heavier ejecta from the Copernicus impact. In this area many of the larger 5-6km craterlets are named as satellites of Stadius (like Stadius G, Stadius T etc) while the smaller ones remain unnamed. Closer in to Copernicus and the larger craterlets are satellites of Copernicus itself. As a young teenaged amateur astronomer I struggled to see these with my 2.4” refractor but here with the 8” f/20 Mak-Cass they are easy to see and study. I encourage you to take the time to do that.
