Strange Artifacts on Exposed Frames - Ice?

Discussion in 'STX and STXL Series Cameras' started by sixburg, Jan 24, 2017.

  1. sixburg

    sixburg Cyanogen Customer

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    upload_2017-1-24_10-6-35.png

    Doug,

    The above is a snip of frame taken on STX16803 last night. I'm not worried about the obvious tracking issues which is caused by the poor weather.

    What concerns me is the pattern that looks like ice. This appears on flat frames as well. The link below is to the FITs files taken this morning with the same pattern....very strange goings on with this camera. Something new every day :-(

    https://www.dropbox.com/sh/i90knxkx5qqfct2/AADHyIr6fHqi0iBznJSKis9ya?dl=0

    Any ideas what's causing this and how to fix it?

    Thanks,
    -Lloyd
     
  2. Doug

    Doug Staff Member

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    Looks like scattered light. Fogged optical surface?
     
  3. sixburg

    sixburg Cyanogen Customer

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    Feb 10, 2016
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    Hi Doug...
    I doubt it's fogged. The RC Optical TIM manages the mirror temps just above ambient. The last time I saw this a couple of weeks ago there's was nothing visible on either the primary or the secondary.

    Could the horizontal stripes seen here be related? RBI issue?
    upload_2017-1-24_13-42-2.png
     
  4. Doug

    Doug Staff Member

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    Okay now that I've seen the FITS image, that is definitely frost. Time to recharge the desiccant. The procedure is in the user manual.
     
  5. marc4darkskies

    marc4darkskies Standard User

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    That's definitely ice / moisture inside the CCD chamber. Seen it many times myself on my STXL. You need to recharge your desiccant.

    Cheers,
    Marcus
     
  6. sixburg

    sixburg Cyanogen Customer

    Joined:
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    Thanks, Marcus...

    As it turns out I have a "spare" 16803 ;-) I can swap the plugs and deliver the offending one into the oven.

    Take care.
     

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