ST 8300M banding issue

Discussion in 'STF Series CCD Cameras' started by Shailesh Trivedi, Jul 2, 2018.

  1. Shailesh Trivedi

    Shailesh Trivedi Standard User

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    I have owned this camera for the last several years and it has given very good service & results.

    For the last few imaging sessions, I have seen random banding issue with my ST 8300M.

    They show up as large horizontal bands that are crisply defined.

    It even shows up in darks & biases randomly.

    Here are two files - one light frame and one dark frame that shows the issue.

    https://www.dropbox.com/s/xxe51qvehmjx8xl/CrescentLight1x1Ha1800.000secs00000004.fit?dl=0

    https://www.dropbox.com/s/i64wt91e2uwsccr/NGC2403Dark1x1Red300.000secs00000074.fit?dl=0

    I use The Sky X for image acquisition. I have tried changing the USB cable, and bypassing a hub and connect it directly to the PC's USB3 port but the issue still persists.

    Next I will try using CCD Ops to see if I can get it to reproduce, if so the issue could be a camera problem.

    Please help with suggestions on how to resolve this issue.


    Shailesh Trivedi
     
  2. Doug

    Doug Staff Member

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    Wow, that's unusual. It looks like flushing is being done improperly.

    First step - download and install the latest SBIG Driver Checker (do this rather than use the update button), and update your firmware and driver.

    ftp://ftp.diffractionlimited.com/pub/SetupDriverChecker64.exe

    Second step - make sure you have the latest hotfix for TheSkyX.

    If neither of those clear up the problem, then please try again with CCDOPS.

    You can do this at your desk since the problem appears in dark frames.
     
  3. Shailesh Trivedi

    Shailesh Trivedi Standard User

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    Hi Doug,

    Thanks for your response.

    What do you mean by "It looks like flushing is being done improperly" ?

    I have the latest The SkyX version.

    I installed the SBIG driver few months ago & did not have any issues with it. The site also says that the drivers for ST 8300M are no longer being updated, so I figured that is what I get, and it works.

    I will try first with CCD Ops to see if that resolves it.

    Shailesh
     
  4. Doug

    Doug Staff Member

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    Before each image, residual charge is flushed from the sensor. This process does not appear to be working correctly. Most likely this would be caused by software or firmware.

    The "SBIG Universal" drivers are still being maintained.

    Doug

     
  5. Shailesh Trivedi

    Shailesh Trivedi Standard User

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    Hi Doug,

    Is the flush to mitigate a RBI issue, which every KAF sensor suffers from in some form? Just curious how it is flushed. Is there a RBI flushing LED? Perhaps that has malfunctioned or is functioning sporadically.

    I will update the drivers first and try CCD Ops as well.

    Shailesh
     
  6. Doug

    Doug Staff Member

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    No, this has nothing to do with RBI.

    All CCD sensors have to be flushed of charge prior to exposing them. Depending on the sensor this process looks a lot like normal readout, except nothing is digitized.
     
  7. Shailesh Trivedi

    Shailesh Trivedi Standard User

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    Thank you Doug.

    Interestingly I see this issue when I take really long exposures of 20 minutes or 30 minutes with Ha filters. I am not sure if that is relevant at all.

    Shailesh
     
  8. Doug

    Doug Staff Member

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    That’s hard to reconcile with the way the camera operates.

    Please try to replicate with CCDOPS. And also can you confirm it only happens on long exposures?
     
  9. Shailesh Trivedi

    Shailesh Trivedi Standard User

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    Doug

    Reporting back on this issue. I tried to update my ST8300M drivers but the system told me that my drivers were the latest. Then I tried CCD Ops.

    I could not get CCD Ops to run as per my needs, so while still using The Sky X with camera add on, I used CCD Commander to add a 25 second delay between two image captures. And after I did this, in the six 30 minute frames I captured overnight, I did not see the banding issue.

    I am cautiously optimistic. I am unsure how to explain this.

    During the past several nights, running back to back images without a delay, shows me a banding issue approximately on the 3rd or 4th 30 minute capture.

    Shailesh
     

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