How to determine correct exposure for flats

Discussion in 'Image Capture' started by Stephen Avery, Oct 10, 2016.

  1. Stephen Avery

    Stephen Avery Cyanogen Customer

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    Chailey, East Sussex, UK
    Hope this is not a silly question, but is there a simple way for MaximDL to determine the correct exposure when taking a series of flats? BTW, I know how to do it using Nebulosity, but it would be convenient to have the same functionality in MaximDL.

    Stephen
     
  2. Doug

    Doug Staff Member

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    I would usually aim for an ADU level around 30,000, as measured by the Information window.

    What procedure are you used to using?
     
  3. Stephen Avery

    Stephen Avery Cyanogen Customer

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    Thanks Doug.

    The procedure I have been using is documented in Craig Stark's reference manual on Nebulosity 4, on pages 28 and 29. He recommends to aim to place the histogram of the image more or less in the centre, "so that the histogram shows all of your values are well off the left and right side. Leave at least a quarter or so of the histogram blank on each side, ideally with it roughly centered."

    I have tried to use the same technique in MaximDL, but am unable to find a histogram display which moves left and right according to the exposure.

    Stephen
     
  4. Doug

    Doug Staff Member

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    View menu, graph window, histogram mode. Aim for the peak of the histogram in the 30,000 ADU range.
     
  5. Stephen Avery

    Stephen Avery Cyanogen Customer

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    Chailey, East Sussex, UK
    Great - thanks Doug.

    Stephen
     

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