Pickering's floral crater

Eratosthenes and environs. December 4, 2011.  22:00-22:30UT. 200mm SCT f/10. 333x 

Eratosthenes is a very dramatic and beautiful deep crater with a well-defined circular rim, terraced inner walls, a central mountain peak, but lacking its own ray system. The sketch, which is my third and best sketch of Eratosthenes so far, was done at relatively low sun-angles to bring out the shadow cast by the crater and adjacent western terminus of the Montes Apenninus mountain range. What makes this formation interesting to sketch is its linkage with the Apennine mountain chain.

In my sketch I tried to bring out the following features:

1. Rays from the prominent crater Copernicus to the south-west
2. Fine detail of the western terminus of the Montes Apenninus mountain range.
3. Numerous craterlets which typify the region around Eratosthenes
4. Internal wall terracing 

Way back in 1924 Pickering noted dark patches in the crater that varied in a regular manner with time. He attributed these mobile patches to around 36 different flowering plants. Check out this old document here written by one of his associates.