[AZ-Observing] Changes in 17P/Holmes in Six Hours
- From: Tom Polakis <tpolakis@xxxxxxx>
- To: amastro@xxxxxxxxxxxxxxx, AZ-Observing@xxxxxxxxxxxxx
- Date: Thu, 25 Oct 2007 7:44:16 -0400
My earlier notes for the comet were taken at around 5:30 UT on the 25th. I
just took a look at 11:30 UT. There have been some changes.
Earlier, I would have put the brightness at only a couple tenths brighter than
Delta Persei, or 2.8. Now I have it as not quite midway between Delta and
Alpha Persei, which puts it at 2.5, or maybe 2.4.
Through the scope, I have been comparing its by using two 10th (?) magnitude
stars within a few arcminutes. In the earlier view, it was located between
these two stars, but has now moved off of this line. Earlier, I could line up
5 shells between the stars; now I would say that value is closer to 3. So that
shell has grown by between 50 and 100%. It's late (or early), so I am hoping
that these are the same two stars, and I'm not just too tired to make a good
observation.
Finally, the fainter "outer halo" that has been mentioned appears to be more
easily visible. The moon's altitude is quite a bit lower, so that could be
helping sky brightness. I don't see anything but a spherical form to this
halo, and have not picked up any elongation or faint tail structure throughout
the night.
Here's one case where it would be nice to live at a more northerly latitude,
where the night would last longer. But then again, there can't possibly be
more comfortable observing weather than what currently exists in southern
Arizona.
Tom
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