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Re: Basic questions...

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  • hilary15xx
    Hi Daniel, There probably is no good answer to your question. It depends on what you are photographing. If the target is very bright, it will cover up the
    Message 1 of 5 , Feb 28, 2010
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      Hi Daniel,

      There probably is no good answer to your question. It depends on what you are photographing. If the target is very bright, it will cover up the dark frame noise, and then a single dark frame might be enough to eliminate hot pixels. If the target is very dim, then more darks will be needed to keep the sky noise down. I have heard it said that a good rule of thumb is to take as many darks as you do lights; but that can be an daunting task. (Maybe I made that rule up myself!) For what it's worth, I typically use 15 frames, and that seems to be enough for my typical targets.

      You might want to look at my SimCCD program, which can give you a feel for what the impact will be if you use too few darks. A beta test version of the program is available at http://www.darklights.org/simccd/.

      Take care,
      Hilary

      --- In ccd-newastro@yahoogroups.com, Daniel Fafard <daniel.fafard@...> wrote:
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      > Hi group,
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      > I ordered today the QHY9 CCD camera.
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      > I would like to know:
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      > How many darks is recommended to do with a CCD?
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      > When doing Ha...Do you do Ha only or we must do L + Ha?
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      > Thanks for your help,
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      > Daniel Fafard
      > Québec, Canada
      > Lat: 46° 2' 50" Nord, Long: 73° 28' 35" Ouest
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