DarkFlats for ASI-Cameras

Discussion in 'Image Processing' started by Horst Ziegler, Aug 19, 2018.

  1. Horst Ziegler

    Horst Ziegler Cyanogen Customer

    Joined:
    Jun 11, 2015
    Messages:
    37
    Location:
    Mondsee Austria
    Hello,

    When calibrating the ASI294 data (and other CMOS Cameras with AmpGlow) , it has been shown that one must never work with bias! So only Masterdark and Masterdarkflat.
    - Masterdark with uncalibrated darks
    - Masterdarkflat with uncalibrated darkflats
    - Calibrate flats only with Masterdarkflat
    - Calibrate lights only with Masterdark and Masterflat
    With that you get the Amp Glow completely gone.

    Where can I tell MaxImDL to use DarkFlats instead of Bias? Are the DarkFlat Images stored as Dark files?

    Are there any fomulas available, how MaxImDL calculates calibration?
    Like : (Light - Dark) / (Flat - Bias) * avg(Flat)

    Thanks a lot in advance
    Regards Horst
     
  2. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    4,634
    Since flats and lights are typically different exposure lengths, simply load up both sets of darks. MaxIm DL will put them in different calibration groups, and will autoselect the appropriate group based on exposure time.

    And yes, MaxIm DL does the expected calculation!
     
  3. Horst Ziegler

    Horst Ziegler Cyanogen Customer

    Joined:
    Jun 11, 2015
    Messages:
    37
    Location:
    Mondsee Austria
    Hello Doug,
    thanks a lot for the quick reply
    Best regards
    Horst
     

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