QHY183M - is this normal or do I have a problem?

I have a QHY183M that I have just started using in SGP Pro.

I have previously been using the QHY183M with other capture software and switching to SGP Pro, I have found I get very different imaging results between using the ASCOM driver and the System Driver.

I have attached two files to show the difference between the two drivers. Is the horizontal banding shown by the ASCOM normal? This banding is not fixed, it moves between images, and the bands can vary in width, so normal calibration doesn’t seem to remove it.

For reference, both images were taken in the other capture software, using the same settings (Gain 11, Offset 30, USB 60, -10 degrees, 120s) and the ASCOM image is identical to the one SGP Pro produces.

I am not suggesting SGP Pro has an issue with the QHY ASCOM drivers, as I can replicate the banding using other capture software. I think the issue might be either the ASCOM drivers themselves or possibly some kind of power issue…

Has anyone else experienced this using a QHY183M with the ASCOM driver.



I’m guessing these are screen captures. Zoom to full scale and I expect it to go away. I’ve seen this on QHY color cameras and believe it’s just an artifact of the fact that the images aren’t deBayered in SGP and the pixels create a Moire’ pattern at lower resolution zooms. Not sure why it would happen the same on the monochrome, but presumably it’s a fact of the SGP reduction algorithm. I note both pictures show the same heat flare I get on my QHY-183C.


Also, the ASCOM driver just sits on top of the Windows or “system” driver - it is just another layer, the communication with the camera is handled by the same code.

No idea why a mono camera should show that pattern, though…

The images are actually Mono FITS file, stretched in PI, and saved as JPEGS, it doesn’t go away by zooming to full scale.

I wasn’t aware the ASCOM drivers sat on top of the Windows driver - learn something new every day!

I use my system remotely, with a stick PC attached the the mount running everything, and I connect to it via TeamViewer from inside. After spending yesterday dismantling everything and testing each part with every other part I have isolated the issue to the USB Hub on the UPB. I have now bypassed that by adding a 3-port USB3.0 hub to the mount and the issue has gone away.

Sorry for wasting everyone’s time.


1 Like

Not at all, also very interesting to know a USB hub can create that effect… weird.

@SimonWhitfield - Not a waste of time at all. Agree with @jaime that it is interesting and good to know. Yet another example of why USB cables, and hubs, should be at the top of the suspect list any time issues are being encountered …


I recently did a set of flats for my QHY22 and saw the same banding when the images were displayed by SGP. When I displayed them using other image processing software, the banding disappeared. My conclusion was that it was an artifact of SGP’s compression of the image to make it fit the display window.