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I do the fridge trick a lot, Tony. It works great.
Just remember to shoot bias frames when you do your images and shoot bias frames
when you do your darks. You need to save the darks with the bias removed. Once
you do that, you can scale the dark frames quite readily. If you have a set of
darks for 30 minutes, you can divide by two to get 15 minute darks. It is a
powerful way to manage the resource.
Also you don't waste valuable imaging time shooting
darks. I like to shoot a minimum of 10 darks and for 20 minute exposures, that
takes a lot of time.
----- Original Message -----
Sent: Tuesday, October 14, 2003 11:05
AM
Subject: Re: [OT] Re: [APML] dark
frames
Steve,
Dark frames are no hassle at
all with CCD's ... you can shoot them anytime the air is cold enough for
the camera to reach the same temperature that you took the images... the
modern software makes combining the frames into a single "super" dark frame a
snap ... I wouldn't let this deter your forray into the dark side ... I even
had the idea of sticking the camera into the refridgerator during the day to
get the dark frames made ... but usually I'll anticipate what I'll be shooting
a few days prior and start running off dark frames while it's the full moon or
cloudy ... flat fields are actually more of a pain ... the best thing here is
to design an optical system where you don't need them.
Tony
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