Comet Tempel 1, July 2, 2005

by Albert Highe

I didn't want to spend a lot of time on this, so I took my 8" f/6 for a quick look up near Montebello. The sky was clear, but about as bright as Montebello gets. Temperature was in the high 60's and RH was 36%. There was no wind.

Finding the comet was challenging. To insure that any observation would be genuine, I did not take a detailed finder chart with me. I knew generally where to look. With a little bit of searching, I was able to catch a glimpse of it at 50X. At 87X I was pretty sure I found it. The best contrast was observed at 135X (9mm Nagler T6). At this magnification, I could hold it with averted vision 95% of the time. It appeared as a slightly elongated faint nebulous patch with an average diameter of approximately 1'. Contrast improved from 9:30PM til about 10:30PM. Thereafter, contrast seemed to degrade as the comet sunk lower toward the horizon. At 11PM it was still "easily" visible (i.e. I could hold it with averted vision about 85% of the time).

You can find a labeled DSS image of the area at:

http://pw2.netcom.com/~ahighe/Tempel1Comet2VII05s.jpg

As you can see in the DSS image, there were some nice reference star patterns nearby.

When I returned home, I confirmed that "The Sky" predicted the comet's location fairly accurately.

In summary:

1. dark skies are essential
2. the comet should be visible in scopes as small as 6" (probably even smaller) if you have very dark skies.
3. in MB type skies, you should use at least an 8" scope, and preferably larger.
4. best contrast appeared to be at moderate magnification (135X)
5. take a detailed finder chart
6. unfortunately there will be no nice star patterns close to the comet tomorrow night.

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Posted on sf-bay-tac Jul 03, 2005 01:11:33 PT
Converted by report.pm 1.2 Sep 26, 2005 20:32:24 PT