Cracked window?

Discussion in 'STX and STXL Series Cameras' started by Tomalley, Apr 22, 2022.

  1. Tomalley

    Tomalley Standard User

    Joined:
    Apr 27, 2020
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    My 16803 camera developed these strange artifacts in each corner of images regardless of filter position or binning mode.
    Mr. Lynch suggest a cracked glass window in front of the ccd. Wondering if anyone has see anything similar.
    upload_2022-4-22_9-19-0.jpeg
     
  2. Colin Haig

    Colin Haig Staff Member

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    What changed recently?

    Best thing to do is pull the camera off the scope, set the filter wheel to a clear/luminance/empty slot, and have a look down the nose of the camera while shooting a long exposure - that way you can see the chamber window and the sensor.

    I doubt cracked glass would have this sort of symmetry, unless there was pressure in the centre of the chamber window or the sensor glass.
    Incorrect use of the Desiccant and Purge Ports could cause a problem. e.g. pressurizing the chamber with dry nitrogen or argon, and overpressuring it.

    Another possibility is a shutter problem or filter wheel movement while shutter in motion.

    The reason I suspect the shutter is the distinct difference in background brightness, in a horizontal line at around 1580 pixels down from the top.
    If the shutter failed to close properly or failed to open properly, and the filter wheel was being changed in position, it might account for the diamond like pattern.
     
  3. Doug

    Doug Staff Member

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    I've seen a cracked 16803 sensor before, and I'm sorry to say that looks ominously similar.

    The time I've seen it was when a customer tried to flush out the chamber from outside with compressed air. The resulting overpressure caved the glass in.
     

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