Hitchhiker's Guide to Rukl Chart 66

Maurolycus and Barocius (David North <d _at_ timocharis.com>)

Maurolycus was only about two-thirds lit tonight, but that turns out to be a good way to see it. The low sun angle exaggerated the definition of the "messy area" in the northwest floor, which appears to be a circular slump, but not clearly an impact. It makes me wonder if the actual impactor that formed this massive plain hit off-center, or if Maurolycus was formed over an earlier, deep impact that created the weakness leading to such a slump. I have no idea. But it makes for a good "look."

Adjacent Barocius also has a similar feature, but more distinct -- it probably was a later impact. But from the look of it, not much later than the major hit. Possibly even a one-two punch. A bit north, Gemma Frisius was also putting on a good show, but considerably less well lit. This afforded a fleeting glance at its curious "squarish" internal craters. There are two similar features, one north and one south. The northern one looks almost perfectly square, with a single distended corner. The southern one looks more like a trapezoid, and a smaller crater next to it also has a curious angular appearance. I have seen this effect before, particularly the crater South near Mare Frigoris, but it usually can be traced to nearby older impacts that deform the walls in this way. But these craters show no such obvious mechanism, and I have no idea why three such are so proximal.

Maurolycus (Bill Arnett)

(Dec 16 0830 UT) The evening shadows in two places seemed discontinuous as if formed by a gigantic flag on a pole on top of the mountains. I really did a double-take. I moved my scope to eliminate the possibility that I was seeing crud on my optics. The weirdness remained. Skeptical of the reality of a gigantic flag, I decided to check the topography in Rukl. He shows a couple of inconspicuous mountains near where I saw my funny shadows. What I saw in one case was the normal shadow from the rim mountains coming up to the base of a mountain which then cast its own shadow a little farther on. In the other case it was a nearly invisible mountain (which just touches the bottom of the "y" of "Maurolycus" on Rukl's chart and is much more prominent there than what I saw in my eyepiece) just east of what seems to be the large central peak (near Rukl's "o"). But the inconspicuous mountain is 3x higher than the obvious one! Very peculiar. I suppose it is the true central peak but it sure doesn't look that way.

See also Morio Higashida's image of Maurolycus.