Resolved ST-2000XCM Vertical stripes

Discussion in 'General' started by Ken Machell, May 16, 2020.

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  1. Ken Machell

    Ken Machell Standard User

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    Hi Folks,
    I have a ST-2000XCM which I have used for about 12yrs with a Celestron C11 SGT.
    Since new, it has had a blue vertical stripe in the bottom half of the images (see M104 attached).
    The images are 1600 x 1200 and the band is in columns 679-681 from row 655 to the bottom.
    Is there any way this can be fixed by a firmware upgrade, cleaning, etc.
    It is pretty frustrating as the camera is a great "out of the box" solution.

    Thanks for your help.
    Ken
     

    Attached Files:

    • M104.jpg
      M104.jpg
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  2. Colin Haig

    Colin Haig Staff Member

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    This is a natural issue caused by a hot pixel - from that image, I see 3 of them. This is an issue that can be dealt with by dithering and post processing.
    Also, check your cooler is running well - it often helps.
    You could post a FITS image and I could take a look.
     
  3. Doug

    Doug Staff Member

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    That doesn't look that bright. First things first... are you subtracting dark frames? If not, then do that. Unless it's really bad it should disappear entirely - and it doesn't look that bad.
     
  4. Ken Machell

    Ken Machell Standard User

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    Thanks for the response guys.

    I have attached the FIT file.
    I can't find a specific dark frame for the M104 image, but have attached another one.
    The band appears in the DF also, so yes it counters the stripe in the light frame.
    I don't have anything that can open FIT files (only a freeware program) so I generally save to TIF which I can't upload here.
    The final image (JPG attached) with DF Subtracted came out ok.
    It has always bugged me that the stripe is there, but if you consider it not bad, then I can live with it.
    I am getting back into photography after a layoff for many years.
    I've been worried that if I start taking multiple hour long exposures and stacking them to remove noise, etc, the stripe will remain.
    I will probably get Maxim DL Pro to process images and see how things go.

    Happy to know I don't need to buy a new camera.
    :)
     

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  5. JoeGafford

    JoeGafford Standard User

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    Ken,

    The dark frame and the light frame does mot match. They need to have the same temperature and exposure times. Your dark frame is a 300 second at -13 C and the light frame is a 108 second one at -12 C.
     
  6. Ken Machell

    Ken Machell Standard User

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    Thanks Joe,
    You’re correct, the lights and darks are from separate images. The PC in my observatory crashed som time back and I lost a lot of data (now I back up to a NAS). I was only showing that dark frame to demonstrate that the banding also appears on the dark.
    They do cancel out when I have matching light and dark frames.
     
  7. Doug

    Doug Staff Member

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    As they should. That is the answer - subtract a dark taken with the same temperature and exposure settings.

    I'll mark this as resolved.
     

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