Resolved Avg ADU dropping after consecutive flats

Discussion in 'STX and STXL Series Cameras' started by Alan Karty, Nov 22, 2018.

  1. Alan Karty

    Alan Karty Cyanogen Customer

    Joined:
    Aug 29, 2016
    Messages:
    86
    I have noticed the following behavior when taking consecutive flats with my STXL-11002 controlled by MaximDL v6.18.
    I took 10 consecutive auto-dark flats of 20 second duration with a constant brightness level. CCD temp at a constant -25C. Notice the average ADU drop with each subsequent exposure.

    1 - 19978

    2 - 19416

    3 - 19211

    4 - 18785

    5 - 18565

    6 - 18314

    7 - 18084

    8 - 17874

    9 - 17632

    10 - 17366


    I have noticed this with both a Flip-Flat and a Gerd Neumann ELP. What is going on?

    Thank you.

    Alan
     
    Alan Karty, Nov 22, 2018
    #1
  2. Doug

    Doug Staff Member

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    Sep 25, 2014
    Messages:
    9,956
    I don't know - that is exceedingly strange. Can you post your raw FITS data?
     
    Doug, Nov 23, 2018
    #2
  3. Alan Karty

    Alan Karty Cyanogen Customer

    Joined:
    Aug 29, 2016
    Messages:
    86
    Doug,

    After further research, it's the ELP that is not that stable. Thank you for your support.

    Alan
     
    Alan Karty, Nov 26, 2018
    #3
  4. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    9,956
    Okay great. Not surprised that was the outcome! Hard to imagine how the camera would do that.
     
    Doug, Nov 26, 2018
    #4

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