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Log, Feb 17, 2006

16 people. The wind was fierce all night long. Usually high winds are matched with very turbulent air, but the seeing varied between acceptable to quite good. For example, the Trapezium showed 4 stars clearly, the fifth star almost always and glimpses of the sixth star.

We showed the public a collection of traditional favorites. We could easily see 6 moons of Saturn, with Iapetus visible if you knew where to look. Cassini's Division was usually easy to spot, but Encke's Division was not visible. The Crepe Ring could be spotted against the planet. M42 and M43 were bright and clear and you could make out a lot of detail. We tried to spot the "Pup" at two separate times - when the visitors were there and later when just Ernie and Mike were around. The "Pup" [Sirius B - the white dwarf star] remained hidden in Sirius A's glare. Sigh - maybe I'll see it someday. We went to the pretty planetary nebula NGC 2440 in Puppis. It is distinctly blue, somewhat similar to the Clown Nebula. We showed to a double double star which I discovered I had not listed. I can't remember which one now.

I intended to go up to GUM-2 a collection of double stars in a diffuse nebula just off the snout of Canes major [Theta Canes Major], but I got distracted. I'll have to remember to try this area in the near future.

We spent a good deal of time trying to spot the Horsehead Nebula but we had little success. We had absolutely no problem centering the object, and we easily spotted the diamond configuration of stars which Ernie knew about. Both a photograph of the Horsehead and the software of Sky Chart 3 showed one of the corners of the diamond sitting just on the border of the horse's nose. We tried the hydrogen-beta filter. It definitely darkened the Horsehead - in fact it darkened everything except the star HD 37805 to invisibility. The contrast was zilch. Without the filter I was able to detect the faintest of faint contrasts between the left and right sides of the image. The "red" section was the smallest bit brighter than then "dark" section but absolutely no border between the two could be seen. This really isn't so surprising. In spite of the glorious pictures of the Horse's head against a flaming red background, the human eye can see little contrast. The problem is that a dark adapted human eye is almost blind to shades of red. So the Horsehead seems like a dark gray against a dark gray background. Sort of finding a black cat in a coal mine at midnight.

There is a very good chance that Frosty Drew Observatory will not be open next weekend (February 24th). Before you come down, look at the webpage to see if we have the "Do Not Open" circle with a slash over the closed dome.

-Les Coleman

Leslie Coleman
Author:
Leslie Coleman
Entry Date:
Feb 17, 2006
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Leslie Coleman's Log
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