Falling almost exactly within a 10° x 10° square at the juncture of three maria - Tranquillitatis, Fecunditatis and Nectaris - is Terra Manna. This chunk of terrain, also known 250 years ago as Colchis, is old and battered. Its interest comes from a few unusual features. Striking diagonally across Terra Manna are three linear rilles that are also old and battered. These Gutenberg Rilles are infrequently imaged (except by Stefan - this is his second LPOD of them!) and are approximately radial to Imbrium and hence probably related to its formation. But it could be that the rilles are older than that - they are pitted by younger craters and have somewhat soft, degraded edges. The other linear feature here is probably a secondary crater chain. It is called Capella Valley and seems to cut through that strange crater. It is strange because of its broad wall and similarly broad central peak with a tiny bright knob on top. The crater-cutting valley points back to Serenitatis and may be one of the few known secondary crater chains from that basin-forming event. Finally, did you notice the Gaudibert look-alike? That peculiar mountain-choked crater has a somewhat similar hill-filled cousin in Censorius C. If you don’t have your Rükl handy that is the crater near the top of the image that is cut by one of the Gutenberg Rilles.
11 September, 2006, 2:35 UT. 10″ f4.8 Newtonian + DMK21-AF0 + Astronomik Red filter + 5x Powermate.
Rükl charts 47
Yesterday's LPOD: A Second Discovery
Tomorrow's LPOD: A Very Tormented Floor