Hitchhiker's Guide to Rukl Chart 71

Schiller (JRF <freeman _at_ netcom.com>)
It's not just foreshortened, Schiller really is shaped like a footprint.
Schiller (...Akkana)
[Schiller sketch] Charcoal sketch of Schiller at sunrise. 8/3/98 with an 80mm f/7 refractor.
Schiller (Bill Arnett)
I took a quick peek at Schiller. Very odd. Rukl calls it a "very elongated crater". But isn't it really two craters overlapping with the dividing wall disintegrated? I can't imagine how such a shape could be the result of a single impact. dt>Schiller (David North <d _at_ timocharis.com>)
[In reply to Bill] I suspect it isn't necessarily an impact formation at all, at least not per se. If you trace Schiller further around, you'll note it's part of a larger dual ring, much like that of Orientale or Nectarum -- but much less well defined. I suspect it's part of the "shock rings" of an older (or at least more obscure) large impact, and may be a slumping feature rather than an impact crater. Though some of the features imply impact, they may have been (a) trigger events for the slumping, or (b) just incidental.

My own ideas; no "authoritative" view is represented here.

Schiller and Bayer (Brent Hutto <BHutto _at_ InfoAve.Net>)
Much more interesting was Schiller - my first really good look at this feature and its North wall neighbor Bayer. The contrast between the long, straight, brightly lighted Southwest wall and the other portions of Schiller's rim was striking. The far Eastern end was deeply shadowed. Another nice contrast was the lighted West rim of Bayer immediately adjacent to the lightly shadowed East end of the area marked "H" on Rukl's Section 71. The small crater marked "B" was easily drawn, as well.

I don't know if it's due to Rukl's choice of projection, the current degree of libration or something else but Schiller and particularly the features to its North are nowhere near as shallow in perspective as they appear on the Section 71 drawing. On my sketch it's almost like I was drawing from a overhead view. It doesn't seem oblique at all next to Rukl's drawing. [Akkana: there was a strong SW libration that night. I agree with Brent that it was much less foreshortened than Rukl shows.]

There's a brightly lighted feature that shows up nicely on the Moon-LIGHT Atlas photograph of Bayer between Bayer and Schiller proper. That ledge inside the Northeast wall of Schiller has a peak or prominance on it that was really catching some early-morning sunlight. I marked it as very distinctive on my sketch and it's just barely hinted at on Rukl. I want to look again when I can catch evening lighting and see if it appears or not.

Finally, the area to the North and East of Bayer has a number of craters shown in Rukl. I couldn't catch any individual features but an entire area, quite large (perhaps four to six times the area of Bayer itself) seemed outlined dimly. I suppose it is due to poor seeing that "A", "F" and "H" weren't seen as individuals but only as a general grouping or depression.

Bailly (David North <d _at_ timocharis.com>)
Bailly is monstrous right on the terminator, a brave and imposing presence. There seem to be striations gouged through it into the nearby highlands, hinting at events of crushing import...

With Bailly's eastern wall just inside the terminator, it has that long low light angle that brings out the best in the fractured features inside. This is another highly underrated lunar view, both from the standpoint of intricate challenge and simple aesthetics.

Also interesting is sunrise over Bailly. Along the internal terminator line we could see what looked like a long line of mountains, presumed to be an illusion created by several small craters and whoknowswhat... a neat effect nevertheless.

Bailly (Brent Hutto <BHutto _at_ InfoAve.Net>)
The two smaller craters inside Bailly (labeled "B" and "A" on Rukl's Section 71) were visible. The smaller "A" was indistinct in the poor seeing but seemed a bit lighter in color than "B" or the floor of Bailly proper. The Northern half of the floor of "B" was in deep shadow and the remainder was similar in color to the unshadowed areas of Bailly. The Southwest rim of "B" was quite brightly lighted by the rising sun.

David North, in a Section 71 entry in The Hitchhiker's Guide, mentions the interesting shadow games at sunrise on the "internal terminator" just inside the South wall of Bailly. I spent most of my viewing time observing the changing shadows along the lighted South wall, which brightly separates the "internal" terminator from the main one.

At 9:50PM EDT, the main terminator and the "internal" one were parallel with quite a wide lighted separator formed by Bailly's South wall. There were two notable exceptions. The brightly lighted Western tip of "B" appeared to be casting a fairly narrow shadow down into the "internal" terminator, across the lighted South wall and all the way to the main terminator. The formed a shadow bridge across the South wall.

As a few minutes went by, a similar bridge of shadow crossed the opposite, Western end of the South wall. At first it was very narrow at about 20% of the distance in from the West end of the South wall. Fifteen minutes later, a wider bridge of shadow had descended to almost cross the South wall but with a sliver of light remaining right up against the main terminator.

I could not tell what features, presumably along the North wall of Bailly, were casting these shadows. In my very limited Lunar observing so far, it was the quickest motion I've ever seen. I guess low-angle light can cause shadows to move with apparent speed several times that of the actual march of the sun across the Lunar surface.

Bailly (Akkana)
A crater I'd tried to identify last month bulged out from the terminator at the end of one of Tycho's rays. This month I did better with the charts; starting from Tycho and nearby Schickard, I identified the bulge as Bailley. When on the terminator, Bailly really stands out, and the two craters (A and B) inside it are easy to see. The floor of the main crater seems smoother near the outside edge, giving Bailly a "concentric ring" effect reminiscent of the concentric mountain ranges surrounding the Orientale basin.

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This page last modified: Oct 03, 2011
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