by Dave North
Jane:
Could they share a slope of a long gone south polar crater, now crumbled into oblivion except for the upswelling landscape? Probably not...
Almost certainly not, per tonights observations. Your original "sequence" seems to hold up under further viewing, but the outer ring is not at all concentric to that sequence, if it is a ring at all. The craters all looked more distinct tonight, and my guess is they're merely a coincidental arc, like a monster version of the inside of Clavius.
Nevertheless, the original weirdness still strikes me as having some common structure involved... the seeing was pretty poor here, so not much detailed observation could be made.
Dave North
San Jose California
128mm Refractor 80x and (briefly) 150x