Log, Sep 9, 2000

13 people. So what else is new, its Friday so it must be cloudy. If I could figure some reliable way to get the word out to everyone, I would open the Observatory on the best night of the week rather than Friday. What is worse, a few kids past their bedtimes on a weekday or a larger number of disappointed kids. Case in point - we had a group of girls visit us last night and the best we could do was show them a blurry image of the Moon. All we could do was show them the stuff in the dome and do a planet recognition with our NASA photos of the nine major planets.

We fooled around with Barry's 8" Dobsonian and Doug's Astroscan. These two telescopes can quickly be swung about to catch the hole in the cloud there and the lightly hazed over area there. I've never seen an Astroscan with as many attachments as Doug had on his Astroscan. I think the attachments outweighed the scope. He had it up to 150 power. It does very well at this power giving a nice clean image (between the clouds) of Albireo, Jupiter, Saturn, M103 and others. Barry's Dob is big enough so that you would expect good results, but the Astroscan was a pleasant surprise. Both outside telescopes were having a fine time splitting Polaris and its companion.

I wrestled with the 16" inside the dome. Now both the Dome (when it isn't hung up on the bent track area) and the scope turn at a sprightly 4 degrees per second. However, it requires constant running in and out of the Dome to find, predict and point the telescope. Hummm!? Where will that nice open area drift? If I swing the scope now will I get to Jupiter while it is clear or should I stay on Saturn? Etc.!

We saw Jupiter (+4 moons) and Saturn (+3 Moons) with occasional bouts of clarity. The bright Moon didn't help. Not one bit. Finally, deciding to fish or cut bait, I tried to do some serious Moon viewing (good-bye sight in my right eye). The area I spent the most time in was Mare Nubium. I must confess that this is an area I have given short shrift to in the past and I wasn't familiar with it at all. With some help from Dave and a good set of Lunar Maps, I began to see more and more detail. [See the sketch]. Mare Nubium is outlined by a series of fairly large craters: A/Arzachel, B/Birt, ps/Pitatus, pt/Parrot, P/Purbach and T/Thebit.

A series of three small craters spans the basin of Mare Nubium running from Birt over to Thebit. Between the next to the last crater and Thebit is the so called Straight Wall "Recta Rupes". The wall is neither a wall nor even perfectly straight. It is a fault line in the Moon's surface. It was beautifully clear due to the angle of the Earth, Sun and Moon. Both Dave and I spent a good deal of time looking at this area. For a while, due mainly to my poor explanation of where to find it, Dave was looking for it near Birt and got confused with the whitish lines (Rima Birt) splashed out by mighty Tycho above and just beyond the area of the sketch.

-Les Coleman

Leslie Coleman
Leslie Coleman
Entry Date:
Sep 9, 2000
Published Under:
Leslie Coleman's Log
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