Odd looking darks

Discussion in 'STX and STXL Series Cameras' started by Alan Karty, Feb 12, 2019.

  1. Alan Karty

    Alan Karty Cyanogen Customer

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    STXL-11002M, all drivers and firmware up to date. Taking 20 minute darks, 1x1, -35C. First 14 darks OK, next four show a progressively longer and darker streak from top to bottom on left side. What could it be? This did not happen with subsequent 2x2 darks, 10 minutes, -35C on same night. I have attached the first (#15) and the worst (#17) images.

    Thank you.

    Alan
     

    Attached Files:

  2. Doug

    Doug Staff Member

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    Please upload FITS frames.
     
  3. Alan Karty

    Alan Karty Cyanogen Customer

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    At 21 MB, the file is too large. Suggestion?
     
  4. Alan Karty

    Alan Karty Cyanogen Customer

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  5. Colin Haig

    Colin Haig Staff Member

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    Hi Alan - thanks for uploading the darks.
    This is unusual - not seen this before.
    Doug may want a few bias frames as well, so we could determine possible cause.
     
  6. Alan Karty

    Alan Karty Cyanogen Customer

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  7. Colin Haig

    Colin Haig Staff Member

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    Thanks Alan. Doug will need to have a look.
    I see the effect in the Bias frame as well. (eg the last attachment it is quite obvious).
     
  8. Alan Karty

    Alan Karty Cyanogen Customer

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    The biases were a set of 25 - I included numbers 1, 9, 17 and 25. I wonder if the effect is time dependent. Focal length 540, Aperture 106.
     
  9. Doug

    Doug Staff Member

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    Looks like something in the electronics is starting to fail. I expect it's one of the regulator circuits that powers the horizontal clock drivers. Could be the drivers themselves, but the ripples I'm seeing suggest poor voltage regulation. Best guess would be a bad filter capacitor.

    What is your camera serial number?
     
  10. Alan Karty

    Alan Karty Cyanogen Customer

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    X15120012
     
  11. Doug

    Doug Staff Member

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    Built in December 2015. All the test data looks good. This must be a random component failure. Sorry for the trouble.

    Please contact Bill @ SBIG Service & Repair, bill@sbig.com to get that fixed.
     
  12. Alan Karty

    Alan Karty Cyanogen Customer

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    Thank you for your assistance. Will do.
     

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