Horizontal bands in light frames with SBIG ST2000XM

Discussion in 'STF Series' started by Konstantinos, Aug 22, 2017.

  1. Konstantinos

    Konstantinos Standard User

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    Hello everyone

    After several years using my SBIG ST2000XM camera, suddenly I encountered a problem of horizontal bands in some light frames. The banding affects just a few frames (2 or 3) of a sequence of 40 frames.

    I would need some support in order to identify the the reason behind this problem.

    Attached you can find some sample light frames that show the problem.

    Thank you in advance
    Konstantinos
     

    Attached Files:

  2. Anthony Ayiomamitis

    Anthony Ayiomamitis Standard User

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    I used to experience this problem many years ago with my ST-2000XM and it turns out that a busy CPU was the culprit.
     
  3. Doug

    Doug Staff Member

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    That does look like increased dark current due to readout delays.

    Modern SBIG cameras have a frame buffer to prevent this sort of artifact.
     
  4. Fred Pastor

    Fred Pastor Standard User

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    Hi Kostantinos,
    Same issue than you, suddenly those horizontal bands with my ST-2000XM appears. I see messages from Doug and Anthony, but doesn't help unfortunately. Then, I was wondering if you have found a solution since 2014... to show me the way in 2019... thanks :)
    Fred
     
  5. Colin Haig

    Colin Haig Staff Member

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    Put the camera on it's own dedicated USB port that is direct to the computer and not on a shared bus, no hubs, no shared USB buses.
    Turn off Windows Power Management - USB Selective Suspend.
    You can use Microsoft USBView utility to determine if you have the camera on it's own.
     
  6. Fred Pastor

    Fred Pastor Standard User

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    Hi Colin, Thank you so much for your prompt message.
    Following your advice, I did a test yesterday with a wonderful night of observation (in the South West of France :)). And as you mentioned, wihout any shared bus. I turned off USB energy through Windows Power Management... and I think this action improved momentarily the situation with less horizontal banding. But after a while, it get back. I have downloaded the Microsoft USBView but to be honest, I am not familiar with this software, at all. It seems that I have only my Sbig Camera connected, but can't translate the rest. I will read the doc manual of this soft. To follow up :) and thanks again. Fred
     
  7. Colin Haig

    Colin Haig Staff Member

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    Fred, you could attach a bias, dark, and light frame using the Upload a File button to the lower right, and we could take a look at the images. Due to their size, you might need to use Dropbox or something like that to share the file.
     
  8. Fred Pastor

    Fred Pastor Standard User

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    For sure let me attach in a Jpeg format firstly and let me know if you prefer a fits format,later. Here are offset image, dark image and NGC1999 region, taken just yesterday. Regarding the bands, I gave up to do the flats. I also attach a copy screen of USB View, considering that in this view that the camera is not connected. Then, I cannot translate if everything is OK, in term of USB connection. Thanks again for your opinion. Fred
     

    Attached Files:

  9. Colin Haig

    Colin Haig Staff Member

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    I'm going to ask @Bill to comment on the horizontal bands in case he has another idea.

    I think it is one of: (a) USB bus problems with the computer, (b) bad cable, or (c) busy usb.

    Turn on all your USB devices, camera, guider, focuser, mount, etc. Then look at USBView again.

    USB View shows:
    Loc 1 = the main USB bus.
    Loc 2 = the secondary USB bus.

    "Loc 11" = USB hub connected to Loc 1, port 1.
    Loc 12, Loc 13 are available - connect a camera here, or to Loc 22, Loc 23.

    Loc 111 ... Loc 116 are all together, on the same bus, so should be at the same speed. You can click on each Loc with a device, and the right hand column will show you "Device Bus Speed:".
    Loc 211.. 218 are all together, on the same bus.

    Is this a special computer or an old computer? What kind is it?
    Are you running Windows 7 or 10?

    Is your computer really busy?
     
  10. Doug

    Doug Staff Member

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    I'd like to see FITS images.
     
  11. Bill

    Bill SBIG Service and Repairs Staff Member

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    Can you give the serial number of the camera? My guess is a failed capacitor in the A/D circuitry.

    -Bill
    bill@sbig.com
     
  12. Fred Pastor

    Fred Pastor Standard User

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    Hi Colin,
    This is a IBM/Lenovo X201 - guess dated around 2013 - and functionning under Windows 7. Rather old but easy to use in a mobile situation. Following you advice, I will try next session a different cable, on a different USB port. I have three port, max.
    @Doug: Here are the fits file, collected last 1st of january. And these horizontal bands are random, and sometimes nothing (at the moment, 20% of a session is cleared of any banding... well meaning that 80% of images goes directy to the dustbin)
    @Bill: well noted, I will give you the serial number in a few hours as this camera is at the moment in my observatory site, in Pyrenees mountains
     

    Attached Files:

  13. Fred Pastor

    Fred Pastor Standard User

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    Here is the second fits file by separate post, regarding the size
     

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  14. Bill

    Bill SBIG Service and Repairs Staff Member

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    I think it's the cap in the A/D. I'm guessing the camera is pre or early 2006 vintage.

    -Bill
     
  15. Fred Pastor

    Fred Pastor Standard User

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    Hi Bill,
    Here is the serial number: 205031036
    Thanks for you message. Can you please precise the "Cap in the A/D" ? Sorry but I don't get it.
    Fred
     
  16. Colin Haig

    Colin Haig Staff Member

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    C"EST un condensateur. En anglais, a capacitor.
    An electronic component that stores a charge.
    It is in the Analog to Digital Converter (ADC) circuit.
    It must be repaired by @Bill
     
  17. Bill

    Bill SBIG Service and Repairs Staff Member

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    Fred,

    Sorry for the confusion. The camera will have to come in for repair. Send me an email, bill@sbig.com, and I will give you the details for doing so.

    -Bill
     
  18. Fred Pastor

    Fred Pastor Standard User

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    Hi Colin, Hi Bill,
    Now I understand :) And if this just a "condensateur" to fix or to change. That is fine. I will then contact you on your direct email. Many thanks again to you, both. Fred
     

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