Changing background values on STi images. Causing guiding problems and star fades.

Discussion in 'STF Series' started by JoshuaHufford, Apr 22, 2017.

  1. Sigg

    Sigg Cyanogen Customer

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    I also had problems guiding and when I checked the guider images I saw the background changes and there were also horizontal lines, but only from time to time. There were several minutes with good images and suddenly the problems were to be seen again. I changed the usb-port, the cables and I also tried a powered hub (no other equipment connected) but nothing solved the problem. But when I took another notebook, everything was ok, no more bad images. The same with another NB. It seemed to me an usb/timing problem. Finally I bought a new NB, again no issues.

    Maybe this info will help you, Joshua.

    Henry
     
  2. Doug

    Doug Staff Member

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    @Sigg, that is potentially a good datapoint. We haven't been able to recreate the problem here, but that could be because there's something about the PCs that are being used.

    @JoshuaHufford and @Kevin Morefield what sort of computer are you using? Brand, version of Windows, 32-bit or 64-bit, and what software are you guiding with?
     
  3. JoshuaHufford

    JoshuaHufford Cyanogen Customer

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    Thanks for your input Harry.

    Doug, the PC that I'm currently using in the observatory I built myself and the components are pretty old. I'm pretty sure the Motherboard is this one,

    https://www.newegg.com/Product/Product.aspx?Item=N82E16813130184

    However I can't confirm this until I'm at the observatory again. I'm running Windows 7 64 bit. I am guiding with Maxim version 6.12, I have also tried PHD guiding with the same problem.

    My friend that I share an observatory with, also uses an STi and sees the same problem, he uses PHD, and we did try a demo of Maxim on his PC and saw the same problem. I don't know all the specs of his PC but he built it himself about a year ago, mainly for gaming, all pretty high end components, I can get those specs from him if you like. We do have another small Asus box PC that we use in the observatory as a file server and other components like the cloud sensor etc hooked to it, next time I'm at the observatory I can try that PC and see what results I get, and I was going to try my friends STi on my PC.

    If you want more specific specs of my PC like cpu, memory, power supply etc. I can get that for you.

    I do also plan to install a powered hub at the pier for the STi to see if that helps any.
     
  4. Kevin Morefield

    Kevin Morefield Standard User

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    Dell tower, windows 7, 64 bit. Guiding with TheSkyX.
     
  5. Colin Haig

    Colin Haig Staff Member

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    Kevin - you can run DXDIAG that comes with Windows, and it will give a lot more detail. e.g.
    dxdiag.png
     
  6. Kevin Morefield

    Kevin Morefield Standard User

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    Thanks Colin - here's the result

    [​IMG]


    Sent from my iPad using Tapatalk
     

    Attached Files:

  7. JoshuaHufford

    JoshuaHufford Cyanogen Customer

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    Just an update, last night my friend was able to put a StarTech industrial powered hub at the pier in the USB line to my STi and it behaved exactly the same as it has been doing, random images of increased noise.

    I have also uploaded the DxDiag from my PC.
     

    Attached Files:

  8. Sigg

    Sigg Cyanogen Customer

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    Location:
    Bad M√ľnstereifel, Germany
    My setup:
    Sony Vaio VPCYB1S1E running Windows 7 Home pro 32 bit
    USB-Realtek-controller
    CCDOps, MaxImDl 6.13
    ST-i, STF8300C

    God Luck!
     
  9. JoshuaHufford

    JoshuaHufford Cyanogen Customer

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    Doug, this problem continues to get worse. What kind of cost are we looking at to send this in? I don't want to put a lot of money into this camera.

    Thanks, Josh
     
  10. JoshuaHufford

    JoshuaHufford Cyanogen Customer

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    Doug please look at these 2 threads,

    http://forum.diffractionlimited.com/threads/periodically-noisy-guide-images.785/

    http://forum.diffractionlimited.com/threads/periodically-noisy-guider-images-with-stt-8300m.2766/

    The OP from the first thread sure seems to have the exact same problem that I am. I knew there were threads in the past describing the exact same problem, I just couldn't find them when I first posted about my problem, so obviously this is not unique to my setup. Can we please have this problem re-addressed so we can hopefully fix it for everyone?
     
  11. Christopher Duffey

    Christopher Duffey Standard User

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    Here is what I think is going on - I will bet money that the frames that are messed up in the ST-i correspond to when your main camera is downloading over USB, I see some USB framing artifacts in the movie you linked - I see similar issues with my ST-i and STF-8300. You could test this theory by running your guiding on a separate laptop/computer than the one that is doing captures - possibly try putting the ST-i and you imaging camera on completely different USB interfaces - no hubs
     
  12. Doug

    Doug Staff Member

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    That's an interesting idea. Joshua can you confirm whether that is the case?
     
  13. JoshuaHufford

    JoshuaHufford Cyanogen Customer

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    Good thought, however I've seen the problem even when the main camera is idle, although it is connected and cooling. I've seen the bad frames come up probably 4 to 5 times during a 900 second exposure, not while downloading. However I can try it with the main camera not even connected.

    I have both cameras on their own individual USB cables connected directly to the pc, although I don't know what is happening inside the pc on usb. The only other usb items I have connected to my pc are a moonlite focus controller and a battery backup power supply. I wouldn't think they would cause much usb traffic.
     
  14. Christopher Duffey

    Christopher Duffey Standard User

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    could be any USB traffic, I see a lot of frame boundaries in your video - you shouldn't see those if everything is working ok, maybe it is just a marginal USB cable. In my case what was happening was that I'd get one of those boundary lines and the software would change the scaling because the image had saturated content in it much brighter than the stars, after it re-scaled the image the tracker lost the star
     
  15. Colin Haig

    Colin Haig Staff Member

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    Joshua, with a utility called USBView (from the Windows Driver Kit), you can see what devices are on which USB bus, and what speed they are running at. That way, you can make sure you arent putting the camera on the same bus as the moonlite or the UPS, so it will run faster
     
  16. Doug

    Doug Staff Member

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    In each of the guider frames, the integrated intensity of the guide stars is very similar. So it looks like the total exposure time on the sky was the same. The background, though, is very different. Here's all the histograms overlaid against each other:

    histo.jpg

    It almost looks like the "dark time" for the exposure was changing dramatically, while the total light exposure remained the same.

    I'm not sure what this implies - yet - but it looks like perhaps the download was being greatly delayed for some reason, and more dark current was accumulating as a result.

    That might make sense if the guide exposure completed during the main camera download. But you suggested that this was happening at random times, not just when the main camera downloaded. (Incidentally MaxIm DL is supposed to reject any guider frames that come in immediately after main camera download.)
     
  17. JoshuaHufford

    JoshuaHufford Cyanogen Customer

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    If I remember correctly the shutter stays open continuously during guiding so shutter would not cause a problem correct?

    I will admit that my PC is really outdated, but it does everything I need it do perfectly well, and controlling it over a slow internet connection remotely the speed of the PC isn't a big deal. If it were just me having this problem I would start there, however my friend that I share an observatory with has a super fast PC built for gaming and he is seeing the exact same problem, and obviously others are as well. I am planning on buying a brand new quality USB cable and connecting it to a different PC to see what happens just to eliminate that as a possibility. Do you have a suggestion on what cable to buy? Anything else you want me to try? I would really like to get this problem fixed as I have a hard time finding bright enough guide stars in my OAG to overcome the noise that comes in from time to time. If this wasn't happening I could guide on a lot fainter stars.

    Thanks for looking into this!
     
  18. JoshuaHufford

    JoshuaHufford Cyanogen Customer

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    Thanks Colin, I will look into this.
     
  19. Doug

    Doug Staff Member

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    The KAI-0340 interline sensors have electronic shutters (frame transfer pulse). The mechanical shutter is for doing dark frames. You could still have the frame transfer happen but then leave the data in the readout columns for a while. In fact the dark current in the readout columns is much worse than the pixels themselves... which suggests that this is exactly what is happening. The question is why?

    As an experiment, I'd suggest running the guider for a bit while NOT running the main camera at all. Just watch the guider frames and see if you get bad ones. Whether it does it or not will be a clue as to what is going on - will eliminate possibilities either way. If it still does it, try disabling all other USB devices on the machine. You might discover that one of them is somehow causing the interference.
     
  20. JoshuaHufford

    JoshuaHufford Cyanogen Customer

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    Clouds and rain tonight but after that it looks like we might have a few clear nights, I'll test this as soon as I can.
     

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