[Aavso-photometry] DSI Pro2

[Roger Pickard]

Hi Keith,
I don't know anything about the DSI cameras but I have done a fair bit 
of CCD photometry and would suggest you lose at least 2 mags with a B 
filter.  Following advice from Mark Kidger in the last issue of TA you 
may be better off using the V and an R (or I) filter.
Norman Walker is still the most competitive supplier of these in the 
UK.  Contact me off list if you want more info.
Cheers,
Roger
-------
Roger Pickard, Director BAA VSS

----- Original Message ----- 
From: "Keith Robinson" <keith.robinson3 at btinternet.com>
To: <aavso-photometry at mira.aavso.org>
Sent: Sunday, July 22, 2007 7:53 PM
Subject: [Aavso-photometry] DSI Pro2


> Hi All and warm greetings from Lancaster U.K.
>
> My wife and I bought a DSI Pro 2 last year from someone who was 
> selling them on Ebay - we paid 400 U.K. pounds (about 800 dollars) 
> for the camera plus RGB filter set. My wife who is Secretary of of 
> our local astronomy club wanted to do the pretty picture thing while 
> I want to do photometry. So I also bought a Schuler V filter.
>
> I've found by doing trial exposrues on open clisters - eg M34 that I 
> can easily reach mag16 with a few stakced 15 second exposures and 
> overall my wife and I are very well pleased with it.
>
> I would like  buy a B and an R filter, however a local amateur 
> astronomer friend would does some photometry with an SBig camera 
> fairly winced at the mention of using a B filter and reckoned that 
> exposures would need to be very long to get to decently low mags. I 
> see that Arne Hendon in his article mentions the camera's excellent 
> blue response - does aynone have experience as to what mags can be 
> reached with a B filter and realistic exposures? I'm using the 
> camera with an 8inch f6 Newtonian by the way.
>
> A final 'by the way' is that with a bit of cardboard engineering and 
> some brown parcel tape, I made a couple of covers which slide over 
> the exposed filters  and certainly eliminate dewing problems.
>
> Many thanks and clear skies - we aint had many of those here in the 
> U.K. lately.
>
> Keith Robinson
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