Holmes from Moraga 10/28/07

Bill Cone

We had enough clear skies up here to pull out the 10", so I managed to study 17p Holmes over a period of about 2.5 hours. There are 3 stars visible inside the halo. 2 of them are E. of the nucleus, the closer one being brighter. The fainter, 2nd star follows that one to the NE, still within the halo. There appears to be a third star that I can only get periodic averted vision hits on that is South of the nucleus, below the fan. The fan, to me, looks more like a circular glow that is decentered from the nucleus to the SW. There is an arrow-like triangle of stars preceding the comet to the West. This is just an amazing object, warm in hue, very soft on its edges, with a stellar core, and several field stars within and without the object. I showed it several times to my wife and daughter, coaxing them outside in their bathrobes to look at it. They were suitably impressed. By my, possibly faulty, calculations (counting diameters across the field), I got a diameter of ~7 arc minutes for the halo.

I poked around the sky for awhile, seeing what was possible with a rising moon, moderate transparency, and a 10" scope from mock rural skies. The answer is: about the same that I could see 2 years ago, when I got back into this hobby. I went after 6939/6946 in Cepheus, and had no better results than before. The open cluster (6939) is barely visible, and the galaxy (6946) is simply not there. I hit a few more targets out of morbid curiosity, and then returned to the comet. I had put a 24mm Panoptic in which gave me a 1 degree field and 63x. This was around 10 pm. The comet had shifted West, and was almost tangent to the Northernmost star of the triangle/arrow of stars that lay just to the W. There was a nice grouping of stars to the N., which helped underscore the contrast in appearance with this object.

It was quite warm tonight, and a few high altitude clouds were drifting here and there. Eventually the moon had climbed high enough to directly illuminate my scope, and I called it quits. It is really fun to have a new object this bright and large to look at from the backyard.

-Bill

Observing Reports Observing Sites GSSP 2010, July 10 - 14
Frosty Acres Ranch
Adin, CA

OMG! Its full of stars.
Golden State Star Party
Join Mailing List		 Mailing List Archives

Current Observing Intents
Click here for more details.