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Log, Jan 12, 2001

30 people. Well this is more like it. I arrived early to find Doug waiting. I fully understand why. After a month of horrible weather the first clear Friday night couldn't have been more welcome. In side the dome we found a small puddle of water on the platform. Luckily we use a belts and suspenders approach to protecting stuff and our rain proof tarps had kept the scopes and electronics nicely dry.

Doug had detoured through Wyoming (the Rhode Island hamlet) to catch the Iridium Satellite. Its huge solar sails cause massive flashes. In this case magnitude -9 40 times as bright as Venus.

We set up Jupiter for a Mom and her two small children to see. What a fine sight it was. You could easily see the Great Red Spot, at least 11 bands with detailed festoons, and the 5 Galilean Moons - you know Io, Europa, Ganymede, Callisto and Huh???. A "fifth" Moon was a background star neatly lined up like the four true Moons. Saturn had four tiny moons in close and Titan farther out. The rings were bright and clear and brought many oohs and aahs from our viewing public.

Our friend Ernie Evans had several objects he wanted to see. In a lull when we had no visitors we turned on a series of deepspace objects. At first we couldn't see NGC281, a diffuse nebula in Cassiopeia. We switched to the Oxy III filter (after Les finally realized he was assembling things in the wrong order - duh...). What a difference. NGC281 leaped out at us looking like a PAC man. We used the Oxy III filter to good effect on the Bubble Nebula NGC7635 near M52. Finally we saw NGC1931 before more visitors arrived.

About this time, Les opened up the Nature Center for a talk on Tides and Tidal Forces. By the end of the hour, the folks who listened understood the way that tides are created. They also learned some odd behaviors of tides in extreme environments. Tidal force is an odd beast in many ways. A byproduct of the excess (or deficit) speed of parts of an extended body orbiting another body, it increases or decrease by the third power of the distance. Almost everything else increases of decreases by the second power. Because of this the lunar tides are more than twice those of the solar tides even though the Sun's gravity is more than 175 greater than the Moon's gravity on the Earth.

Doug and Dave held sway at the 16" SCT during this hour. They went over to the Horsehead Nebula (IC 434) which while very large is very low contrast. After some debate, the consensus was that it wasn't visible due to the Moon's glare. Rigil was split, although a moderate amount of twinkling occurred. With a close double like Rigil, people walking under the telescope are enough to obliterate the split.

R Leporis (Hind's Crimson Star) was the next target. This star is an extremely deep red with an index of +5.69 (B-V). Since most stars never get redder than about +2.5 R Leporis is really unusual.

This week's faintly coveted "Smudge of the Week" was easily won by the Flame Nebula NGC2023. Basically it was a washout. We went to M37, but had a unpleasant surprise as people lined up to watch it. As it approached the Zenith, the diagonal came closer and closer to the telescope's yoke. Only some eagle eyed members realized how close it had gotten (less than a quarter inch) and carefully backed the eyepiece away from danger. We displayed M35, M46, NGC1647 next. They were all very fine viewing. We split Alnilam (Eta Ori) next.

Several members had said they had never seen any trace of nebulosity in the Plieades [M45]. Les said that he had had success in the past with Merope, so we tried it again and the nebulosity, while faint was quite clear.

We had put off the Moon as long as possible. We searched the terminator for interesting craters. However, it was Posidonis which was really quite far from the terminator which drew they most interest. It looked something like the following sketch.

We left before 1 AM, delayed slightly by a gate frozen into position.

-Les Coleman

Leslie Coleman
Author:
Leslie Coleman
Entry Date:
Jan 12, 2001
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Leslie Coleman's Log
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