[Aavso-photometry] UBV Photon Counting

[BailyHill at aol.com]

Hello Jeff;

Saw your note about not finding comp stars within the field of your ccd 
camera and c8/lx90.  I too have been doing photometry from the suburbs of Boston, 
and doubt if Phoenix could be any worse.

Were you using AAVSO "F" charts.  I find that I use them exclusively.  There 
are comp stars within a 10-12 arc minute field.  Most of my program stars 
(CV's and faint LPV's) actually have a comp and check star within 3 or 4 arc 
minutes.  I am using a field of 9 arc minutes (10mm chip and 3570mm focal length).

Is your ccd field smaller than this?

CCD photometry with a c8/lx90 focal length scope is certainly very doable.  
Hope this helps.

I have no comment on your U and B transmission question with the lx90.   
Perhaps it has something to do with the material for the corrector plate.

Clear Skies

Gary