6/20/97: Tracing the profile along the terminator was particularly interesting:
the flatness of Orientale, then a steep drop to the valley to the south,
then two rises where the concentric mountain ranges stood in relief
against the unlit limb, and a pair of long dark streaks extending further
northward, perhaps ejecta from the event which formed Orientale.
Two craters stood out prominently off the north edge of Orientale, both with
huge central mountains nearly filling the crater ("central peak" doesn't
do justice to these peaks). Rukl is difficult to read for "far side"
features, but I might guess that the crater to the southwest of Grimaldi
and inside the concentric rings of mountains may have been Maunder
(on Rukl's Libration Zone VII map), or possibly Kopff; it stands out
very prominently, and Rukl gives no hint of the central peak being so huge
in comparison to the size of the crater.
The one to the northwest could have been Schluter.
Orientale can be an interesting area even when several days off the terminator, if the libration is favorable. On June 10-11, '98, with the terminator several days past, I made a sketch of all the landmarks I could see in the VX102, to see how far into the Orientale basin I was seeing. Not much of the mare itself, as it turned out.
But all that is secondary to the sheer size and form of Mare Orientale, which requires nothing more than good binos, really. This libration was good enough to get a very full feel for the roundness and the look of the shock that would be required to form such a structure; it's just plain awesome.
|Chart 49||Moon-Lite Atlas for chart 50||Chart 51|