[Aavso-photometry] UBV Photon Counting

[Jeff Hopkins]

Hello Arnie,

Thanks for the response. I will be interested in hearing what you 
find with the more popular CCDs.

I agree "dead" is ambiguous. However, I would be interested in 
knowing how practical U band work is with different CCDs for say 3 
magnitude stars with an 8" telescope. I realize if the star is bright 
enough and with a sufficiently large aperture, you can probably get a 
U band response with most any detector, but weather it is really 
usable or practical is another matter. I understand the QE of CCDs is 
higher than a PMT, but then the CCDs outputs are analog and cannot do 
photon counting.

Jeff

At 11:50 -0700 1/19/05, Arne Henden wrote:
>SITe/Tektronix thinned, backside illuminated science CCD.
>The Marconi/E2V chips have similar response.  I've been
>testing some of the newer CCDs, such as the SXV-H9, ST-7XME and
>Meade DSI, and find they have U response, probably adequate
>for brighter targets.  "Dead" is in the eyes of the beholder.
>You might think a PEP system has more U response, but in
>terms of absolute quantum efficiency, many CCDs come pretty
>close.  More on that in the future.
>Arne

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

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