L20: Posidonius

This very impressive crater on the north-eastern shores of Mare Serenitatis was captured on a night of average seeing. Still quite a lot of detail was visible. Part of a secondary inner ring could be traced on the east and west side, and the small crater (Posidonius A) near the center was very prominent. The rilles crisscrossing the crater floor couldn’t be resolved.

Sketch made on 25 January 2015 (d5) using a SkyWatcher 10″ and a TeleVue zoom 3-6 mm.