Help in solving the issue of SGP & qhy9s

hi all

after receiving the second new replace qhy9s-m, i start testing it with SGP software and again i found white horizon pattern (banding) in bias frame & dark frame , and this is the second time and second camera that i notice the problem appear(this is the reason that i send back my 1st camera to be checked by qhyccd)

, i start thinking that the cause from ground loop issue is the main problem , but after some days of testing ,and changing power supply , i found there is no issue when i use qhyccd original software , the white horizon pattern (banding) issue not appear in it,( also the technical team of qhyccd didn’t found any issue with camera when they use the original software)

i don’t know if SGB software have a bug or problem when using qhy camera’s or it’s hardware issue that qhyccd have it with other software

so i would like from all to help me to diagnosis and analyze this case with SGP software and qhy9s camera , and i can provide remote access to test it too

best regards

I guess the original SW uses a direct driver and not the ASCOM driver. Can you try to reproduce the issue with another capture SW that uses ASCOM instead of QHY direct driver? You can try nebulosity or even PHD2 should be able to drive your camera via ASCOM.



One thing to keep in mind is that SGP is not image processing software. Their “stretch” routines are probably not as sophisticated as those in dedicated imaging software. When I compare the “look” of a raw frame in SGP to the way it looks in PixInsight, there is a substantial difference. I suggest you evaluate your bias and dark frames in your imaging software to get a better feel for their quality.

It is also important to remember that ALL ccd chips have manufacturing artifacts. These are not considered to be defects by the manufacturer or the vendor but those artifacts produce “stuff” you can see in a downloaded image. This is why bias, flats and darks are so important to producing the finished image.



A couple of things to try:

  1. In the ASCOM settings, make sure that “No USB During Download” is checked.
  2. Try toggling the “Clamp” setting
    3)Which download speed are you using? QHY recommends that you use “Normal”. Fast or Slow can cause the same kind of banding issues.

Finally, as Charlie pointed out, the stretch that SGP applies can be pretty extreme, particularly if you use the High setting. If you are seeing the same artifact in the same place in bias and dark frames, it ill calibrate out of the image frames.


This is true. Our stretch is a basic linear levels adjustment. It is good enough to see what you are imaging… how it is framed, if something is VERY wrong, etc.

hi thank you for you reply

i try the setting that recommend, but i do not know how to solve it QHYCCD has replacement with new camera but i find same issue now with it !!!


i will try nebulosity day and will update the post

when i taking bias & dark frame i ca see a Bright horizontal streaks in the frame???,so How to solve this problem ?? if is there ???/


because of i do not have other software than Ezcap ( QHYCCD ) & SGP software, i opening the images that i get for SGP in FITS Liberator,and can not noted any of the Bright horizontal streaks, is there any test can i do to find if the camera have any bending issue ??? or earth loop ( ground loop )

This is not a software issue with SGP or the driver. What ever is causing the band is probably a power supply or USB issue. The software from both companies is well established and is not a problem. Low voltage or ground loop on the power supply or interference on the USB. I would be looking mostly at the power supply. Switch out the 12vdc supply and recheck. Work with the vendor to switch out your DC 201 supply if all else fails. Also try removing the camera from the scope and mount so that it is completely isolated. See if you still get the band. If you don’t one the power supplies you are using is causing the problem. Also make sure all of your equipment is plugged into the same power strip with one common ground.

The way to test for ground loops is to power everything up but disconnect all USB connections. Take your DC voltmeter and measure the voltage from the ground side of your DC power supply ( just pull the power connector out slightly to access the ground side) and the ground side of each of your USB cables. If any voltage is present you have a ground loop.

Just my two cents… Bruce Morrell

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thank you Bruce

what is the voltage reading on output 12vdc mast by ??? , From your experience??? loss than 12v or high than 12v ???

It needs to be zero, no voltage…If there is voltage, current is flowing, and in the wrong places…

Bruce Morrell