[Aavso-photometry] UBV Photon Counting

[Jeff Hopkins]

I just joined the list and have read through the archives. Am I the 
only one in the world doing UBV photon counting photometry?

I've tried the CCD photometry, but because my observatories are in my 
backyard in the middle of Phoenix,AZ I am limited to bright stars. 
Finding suitable comparison stars for bright stars within the field 
of a CCD  is near impossible.

FWIW, I recently has some problems with the tracking on my old orange 
C-8 and purchased a new Meade LX-90 just before Christmas while it 
was on sale. The LX-90 is a great telescope and I love the computer 
control, however when I replace the C-8 with the LX-90 and did some 
UBV photometry I was disappointed. The U band reading on the same 
star, same air mass under similar skies is about half that of the 
C-8. I checked a couple different stars and they all showed the same 
decrease in counts for the LX-90. The V band is actually higher a 
bit, but the B band also is reduced, but no where as much as the U 
band. I have since worked on the C-8 drive and am now back to using 
it. The LX-90 will be great for star parties.

I'd be interested in hearing from anyone who is doing UBV photon 
counting. I know equipment for that is hard to find, but really 
pretty easy to make. I designed and marketed a unit back in the 
1980's and have another design I have been toying with.

Jeff

-- 
Jeff Hopkins
HPO SOFT
http://www.hposoft.com/Astro/astro.html

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