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Mooning

Actual Observing

Dave North


 

How about that October eclipse huh? Don't ask me; I didn't see it at all. The clouds were so horrid that I couldn't imagine anyplace near enough would be clear, but I was wrong wrong wrong.The intrepid observers who charged up to Montebello got a reasonably good look. And I had thought about going ... ah well.

In December's list of Things I Won't See, central and eastern US observers get a shot at the Moon occulting Jupiter. But it won't be visible here.

There will be exceptional tides on the 12th for those who follow such things (full Moon and perigee thang). And for Christmas you get an exceptionally high nearly-full Moon to cheer things up!

Just for your amusement, I recorded a sort-of-random observing run so you can see what the life of a loonie is really like. I chose this night in particular because it's near the full Moon, when most people think there's nothing to see. The Moon was over 12 days old; less than two days shy of full.

The 'random' aspect? I picked the date beforehand, and resolved to write up whatever happened. Including a washout. Sort of an experiment.

Date: August 27 (eclipse -2 months)

Equipment: Takahashi FS128 on Losmandy G11 with Televue 7mm Nagler

Q: Dave, aren't you always saying the Moon is telescope friendly and any old light bucket will do?

A: Yes, I often say that.

Q: Then why are you using a Tak?

A: Well, I have one. It's easy to set up. I'm lazy. And I like it. Gives nice views.

Q: Why a Nagler? Don't you have better planetary eyepieces?

A: Yes, I do. But the Nagler is pretty good and on less-than-great nights it does about as well as anything. Then there's the wide field. Do as I say, not as I do!

It was one of those evenings that's warm and still, which often means the seeing will be outstanding. One of those nights when you expect to see tiny little specks of detail everywhere.

Q: So Dave, how was the seeing?

A: Not very good.

Q: Hey, you've been doing this for a while. You're supposed to know when conditions are going to shine. What's with that?

A: Apparently, I'm not that good at it.

Q: My faith is crushed. Could you see anything?

Glad you asked. In spite of the Aristarchus Plateau showing well, the first thing that caught my eye was Rumker -- the biggest "dome" up there. Well, it's really a complex of volcanic domes, but it's so weird I always enjoy getting a look at it. Looks like a giant crab attacking Mare Imbrium.

Speaking of Imbrium, the next place I lingered was on Mons Gruithuisen, also volcanic, which can show central craters in excellent conditions. Not tonight. But out of my peripheral vision I noticed in the early sunrise of Pythagoras that its central peak was just barely peeking into morning, a tiny white dot. Neat!

But one can hardly avoid Aristarchus and Schroter's Valley for long when they're in view at all. For one thing, Aristarchus is about as bright as it gets on the Moon. For another, I simply have to spot the Cobra Head and soak in the view. Even after all these years, it's that good.

Q: Um Dave, the Cobra Head?

A: What, you don't know?

The Cobra Head is the 'source' of the 'rivulet' Schroter's Valley, which is probably a huge collapsed lava tube complex. The volcano has a sunken 'hood' around it making the whole thing look like an excited King Cobra. Really!

Then I hit paydirt. Cruising the area of Sirsalis to get a glimpse of the nearby extraordinary rille -- it's best the day before full, but what the heck -- I noticed that Schickard seemed oddly blotchy.

It was! Sunrise was pretty much complete, but the light was not yet spread evenly over the curved floor. Schickard is big enough that the curvature of the Moon becomes significant.

Q: Significant?

A: The Moon is small compared to earth. Something that big -- 227 Kilometers (about 140 miles) -- would show some curve here on Earth. On the much smaller Moon ...

In this case, significant enough that the terminatorward floor still had lots of small shadows that cumulatively gave the impression of darkerness from this distance. As I watched, I could see this blotchiness fading in a matter of minutes!

Nifty. That's just the kind of Transient Lunar Phenomenon I really enjoy. And quite frankly, most nights you'll see something like that, be it a ray, something off the terminator poking into light ... lots of different things for the alert observer, and sometimes even me.

Since it was just Moon observing, I wrote the notes directly into my office computer. Just look for a while and wander back into the fully-lit office and type a few lines.

Moon observing suits the lazy. Trust me, I know.

 


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