What did you see?! A little lunar detective story

I'm a great believer in preparing well before you go out to observe – but I don’t always do it and even when I do, I leave myself open for surprises because trying to figure out exactly what it is you are looking at can be as much fun as looking at it.

As I wrote na href="http://www.giveyoujoy.net/awe/blog/archives/2007/02/so_long_scar_he.html"> an earlier post, I had a good time the other night tobserving the Alpine Valley and preparing for it by learning current and older theories about its formation. But in the process of observing it, my eye wandered south and latched onto a scraggly area of unusual texture and color. I wrote myself a few notes about it and moved on to other stuff. Then I heard from Bob Magnuson, who was observing with a group from ASSNE, the local club, a few miles away. Bob wrote:

Thanks for the updated info on Valles Alpes. I'm sure you saw all the
details that I saw, and probably were as awed as I at the shadows behind
the Alps and especially Mons Piton. We kept coming back to Archimedes and
watched the terminator move from one side to the other. Seems it must move
right about 10mph, since Archimedes is 50 miles across.

One point of interest is an extensive wrinkle system on Mare Vaporum that
VMA Pro and my sole moon chart do not show. It is in the Hyginus area, but
not a name in sight. Does Rukl have anything on that? . . .

I replied:

I think I was looking at the same wrinkled area - fascinated by both the texture and the different coloration. My notes put it roughly between Triesnecker and Manilius. . . but the bottom line is I could find nothing in Rukl - that is, no named feature - that fit what I thought I was seeing.

I left the email hanging at that point and went looking through charts and books. Then I returned.

Ahhhhh ... I think I just found the key in Wood, "The Modern Moon," p. 60 -

The rough terrain south of the crater Manilius is obviously ejecta from the Imbrium basin, but it has been subsequently coated by a layer of dark ash. On the east side of Vaporum the dark material partly covers the mare and is apparently thicker on the patch of subdued hills that separate Vaporum from Aestuum. . . . Small rilles and domes can be seen in some of these dark deposits. .

That at least fits what I was looking at – still not positive we're talking about the same thing, though ;-)

Bob replied:

We are talking about the same thing, Greg. Right between Manilius and
Triesnecker. Triesnecker and Rimae Triesnecker were among my targets last
night for the Lunar II Club for the Astro League. The color was so obvious
last night with the position of the sun that it just pulled the eye to it.
At first it looked like the dark reddish that the Aristarchus plateau
sometimes exhibits. Must be a trick of the sun angle. It was so striking as
to be puzzling why it doesn't have a name. It really looked like a
corrugated roof with the way the sun was hitting it. Or maybe a corrugated
roof after a tornado ;-). It is certainly a rugged-looking piece of
terrain. What I wouldn't give to walk that territory... I did try for the
astronaut program while I was in flight school. They wanted an engineering
degree, though. One of my jogging partners, Tut Fitzpatrick made it in
1975, but I don't think he ever got to space. Many, many 'astronauts' did
lots of earth-based test flying and never got on a space crew.

I especially like Bob's description of this area – fit my experience, but his words capture it better. This also is a great example of how fascinating the moon can be. Things look so different from night to night – even hour-to-hour. And when you get on the other side of the full moon, you get the same areas highlighted in sequence by long shadows, but from the other direction. First you see them as the sunis rising, then as the sun is setting. It's amazing how areas you are absolutely familiar with one night can look so different – and confusing – the next.

Oh – and photographs and maps aren't as much help as you may think because the maps are simply representations of the terrain – and the photos almost always seem to be taken at a different time than when you are looking. Still, I wouldn't want to do without them, but in this case it was strictly words that helped me get a handle on what we were seeing – the words of the lunar scientist, Robert Wood and the colorful description of another observer, Bob Magnuson.