[AZ-Observing] Re: Comet Lulin

I arrived at Sunset Crater National Monument at 1:30 AM Friday  
morning for a marathon session with the comet. I brought my 8 inch  
Dobsonian, 15 x 70 binoculars, and SkyView Pro mount for some  
photography. While setting up my equipment, I gazed at Virgo and  
found a soft smudge west of Porrima and Eta VIR. A quick look with  
the binoculars confirmed the naked eye view of the comet. Slightly  
blurring my vision made it appear similar in magnitude to Chi VIR-- 
about 4.8 - 5.0 mag.

While the photography session was postponing dark adaptation, I  
worked on a naked eye sketch--which I finished about the same time  
that the 11 degree F temperature killed both of my camera batteries.  
The comet moved significantly in each of the 10 minute exposures, but  
doesn't appear too distracting in the final image.

Once my camera was cold and dead, I moved on to the binoculars. The  
linear structure formed by the tails on both sides of the comet  
appeared very strong at first glance, like a softly glowing horizon  
with a subdued but lustrous sun rising in the middle. Trying to pin  
down position and size on the eastern dust tail was wonderfully  
straightforward. The ion tail however, was still more of a horizontal  
suggestion than a definite structure. Despite that difficulty, it  
appeared longer than in my previous observations since it has gotten  
brighter...and greater foreshortening is probably helping that.

Finally, I worked on a telescopic observation with my 8-inch  
Dobsonian. It was great to see how large the comet had gotten. I  
observed at my lowest power, 37.5X with an 88 arc-minute wide field.  
The comet's tails overflowed the view and the coma blossomed to an  
apparent size of about a 50 arc minutes. The brighter inner coma was  
about 20 arc minutes in diameter, and possessed a stellar  
condensation at this magnification. Taking a detour to 240X provided  
a better look at the central condensation which then appeared as an  
extended object, perhaps about 4 arc seconds in diameter.

Returning to low power, the dust tail was magnificent and filled the  
entire field even when I moved the core of the comet out of the way.  
The northern side of this tail appeared heavier. The ion tail was  
very troubling to pin down. The side of the field west of the coma  
was lighter, and I could see a main axis to the tail dragging away in  
that direction. However, a nagging light area kept drawing my eye on  
the north side of the ion tail, close to the coma. I wondered if any  
nearby stars were creating an illusion, but it was persistent, so I  
included it in the sketch. PA for the dust tail looked to be about  
110 degrees, and the ion tail spread from 290-320 degrees.

This really is a fascinating comet. If the weather cooperates, I'd  
love to see what the tails look like on Feb 25--I wonder if the ion  
tail will look like a splatter or an odd set of splines surrounding  
the coma.

The sketches, photo and full report can be found here:

http://www.perezmedia.net/beltofvenus/archives/001304.html

Clear skies,
Jeremy Perez
http://beltofvenus.perezmedia.net
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