[Aavso-photometry] Video photometry

[Juergen Liesmann]

Hi Brian

>I have been monitoring this mailing list for awhile, and have only been an
>AAVSO member for a few months.  Perhaps this has already been discussed, but
>I was wondering if there is anyone out there who has attempted video
>photometry?  I do not have a CCD camera, but have a Stellacam II and a ubVri
>filter that I use on my MK-67 Mak Cass.
>
>Is there a chance that I can contribute to your work in variable star
>photometry with this setup?

I think you have a good chance.

Arne Henden wrote:
>   Normally, video cameras have a number of non-photometric attributes:
>gain control, antiblooming, nonlinear response, high noise since run
>at video rate, limited dynamic range (often 8-bits).  As such, they
>are not often used for precision photometry.

The Stellacam II has manual control for gain and gamma, no problem.
You must check the maximum value per pixel, that is not in the 
antiblooming range. High noise is a problem, use a (very) good
capture card. Capture cards with a BT848/BT878 chip deliver only 6 bit
in the luminance chanel. And add some pictures to one. You need
more time for a measuring. If a cooled CCD-cam needs one 30 sec. 
picture for a measuring, you must add pictures from 10 or 20 min. 

There a dark pixel on the left and right side off bright stars.
I dont know if is a problem or not, check it.

Look at (join the two lines):
http://www.koschny.de/Astronomy/Cameras/Watec/
MET-RSSD-PA-002_1_a_Comparing_two_potential_meteor_cameras_2004Jan06.htm

Clear skies
-- 
Juergen Liesmann
Hauptstr. 22
27248 Ehrenburg
Germany
Tel: 04275 / 96 30 30
http://www.ra-dec.de