Resolved Brand New STF-8050SC Issues

Discussion in 'STF Series' started by Curt Morton, Aug 6, 2019.

  1. Curt Morton

    Curt Morton Cyanogen Customer

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    I received my new STF-8050SC Friday and put it into service this past weekend at our observatory under the dark skies of Chiefland, Florida. Besides having to figure out how to "Convert Color" for the Sparse Color chip (deselect auto camera selection and instead select "Generi Sparse Color" in the drop down menu), I immediately discovered a couple of issues:

    1. When shooting a bright star for focusing, there is a significant white line throughthe star from left to right. I typically use3 second Bin4 exposures. See attached image.

    2. There are spikes extending off the right side of all the stars. I first noticed it when shooting 5 and 10 second subs to frame my target. The framing subs are shot Bin4, but the spikes are evident in all binning modes. See attached images.

    3. The imaging chip was apparently installed upside down. I installed the camera in the proper orientation on the mount (tripod mounting hole down), and when imaging on the east side of the pier plate solves indicate that the camera is inverted. Likewise, plate solves for images shot on the west side of the pier indicate that the camera is right side up. These results are the opposite of what I get for the other 3 camera I use for imaging.

    Since the camera is brand new, I'm hoping we can resolve these issues quickly.

    Curt Morton View attachment 6067 View attachment 6066 View attachment 6067 View attachment 6066 View attachment 6067 View attachment 6068
     

    Attached Files:

  2. Doug

    Doug Staff Member

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    1. That bright star is massively over-saturating the sensor. Try using a 6th magnitude star. Also when focusing you should not be using high binning; that makes it impossible to tell when you are in focus because you have much less resolution.

    2. That doesn't look right. Could you please upload a FITS file so we can have a better look at it?

    3. That is the normal orientation for the sensor in this model. It would not work at all if it were installed upside down.
     
  3. Curt Morton

    Curt Morton Cyanogen Customer

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    Thanks for the heads up on focusing, Doug. I'll make sure to follow your instructions. I'm glad the sensor orientation isn't a problem.

    I've attached the raw FITS image at 10 seconds Bin4 and a raw 900 second Bin1 image. As you can see, the spikes definitely affect the roundness of the stars in the 900 second image and consequently in the calibrated and stacked result.

    Let me know if you need anything else.

    Curt
     

    Attached Files:

  4. Doug

    Doug Staff Member

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    I'm going to ask @Colin to have a look at your images, and at the original test data for your camera.
     
  5. Curt Morton

    Curt Morton Cyanogen Customer

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    Great, Thanks, Doug. Let me know if there's anything I can do to help.
     
  6. Colin

    Colin Staff Member

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    Private Message sent Curt.
     
  7. Colin

    Colin Staff Member

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    Private Message sent Curt.
     
  8. Curt Morton

    Curt Morton Cyanogen Customer

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    I've submitted the RMA request.
     
  9. Doug

    Doug Staff Member

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    We just ran a suite of tests on your camera. It was a bit unusual - we had to use an artificial star to recreate the problem.

    We think we understand what is happening, and will hopefully have it resolved shortly.
     
  10. Curt Morton

    Curt Morton Cyanogen Customer

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    That's great news, Doug. I'd appreciate an update of what the problem was and what you did to fix it when you're satisfied that it's corrected.

    Curt
     
  11. Doug

    Doug Staff Member

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    We already have a fix and it works. It was a minor issue with the time constant of the DC restoration circuit. I won't get into the gory technical details but this just requires us to change two capacitors (two because it's dual readout). We can change the capacitors without fully disassembling the camera, which makes this a very easy fix.

    We hadn't seen the problem before simply because there is some variability from camera to camera, and it's not always visible. With this little fix it is completely gone.

    Sorry for the inconvenience. Your camera needs to go through the full QA tests again and then we'll get it sent back to you.
     
  12. Curt Morton

    Curt Morton Cyanogen Customer

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    That's awesome news, Doug. I really appreciate your speedy efforts to resolve the problem. Looks like I'll be able to give it a good first light run under the next new moon in a couple of weeks if all goes well with the QA tests. I promise I'll send along my first light image when I have it completed.

    I'm excited about the capabilities of the new camera and I'm looking forward to making it my workhorse imaging camera.

    Curt
     
  13. Curt Morton

    Curt Morton Cyanogen Customer

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    Doug,
    A quick question - should I re-shoot my darks/bias frames for calibration due to the repairs you've made?

    Curt
     
  14. Doug

    Doug Staff Member

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    I would redo them, just to be on the safe side.
     
  15. Curt Morton

    Curt Morton Cyanogen Customer

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    Ok, thanks. Will do.
     
  16. Curt Morton

    Curt Morton Cyanogen Customer

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    Will you notify me when it's on its way back to me?
     
  17. Doug

    Doug Staff Member

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    You will automatically get a tracking number.
     
  18. Curt Morton

    Curt Morton Cyanogen Customer

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    Ok. Great. Thanks.
     
  19. Curt Morton

    Curt Morton Cyanogen Customer

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    Any updates on the status of my camera? I was hoping it's on its way back to Florida by now.
     
  20. Doug

    Doug Staff Member

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    It’s in process. Should be shipped out early next week.
     

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