[AZ-Observing] Re: Changes in 17P/Magnitude

Hello Brian,

This was CCD photometry with aperture diameter of 8 pixels and 
annulus at 15 pixels. The is at f/3.3 with 12" objective., with a DSI 
Pro camera.

Need anything else?

I can change the settings for a larger aperture if need be and get 
the data again from the image.

Jeff

At 11:00 -0700 10/25/2007, Brian Skiff wrote:
>>>   >At UT 25 October 2007 06"00 V= 2.362  ....
>
>      Jeff, for this to be useful we'll need to know the aperture used,
>that is, the diameter of the photometer diaphragm (analog or digital).
>The comet magnitude will depend greatly on how much light is
>included, much as with a galaxy magnitude.  Even better would be
>to have several progressively larger apertures so one could
>contruct a curve-of-growth plot that could be expolated to a
>true "total" magnitude.
>
>      When I went home this morning about 2am, I too noticed the comet
>was brighter than in the evening, and in any case, brighter than
>the earlier reports from Japan and Europe, so we may have been
>lucky in catching it near peak brightness.  As Tom implies, the real
>fun may be still to come as the coma changes structure and the
>outburst event evolves.
>
>\Brian

-- 
Jeff Hopkins
HPO SOFT
Counting Photons
http://www.hposoft.com/Astro/astro.html
Hopkins Phoenix Observatory
7812 West Clayton Drive
Phoenix, Arizona 85033-2439 U.S.A.
(623)849-5889
(623) 247-1190 (Fax)
www.hposoft.com
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