QHYCCD

QHY10 strange behavior

QHY10 strange behavior
« on: October 11, 2019, 06:07:49 pm »
Hello,

I have a QHY10 that has not seen much use since I acquired it a few months ago. The times I've used it, I've not obtained reasonable results. I typically use gain=0, offset=123. These were set early on by following QHY's recommended method of setting these two parameters. What I've observed are two problems:

1. Color gradient visible across images. This gradient is not removed by calibration frames.
2. Exposure time setting in EZCAP and through ASCOM (APT) does not seem to change the captured image much - certainly not as much as one would expect.

To root-out the problem, I put the 10 on the bench and attached a Canon 28mm lens. I ran a series of light and dark frames over several exposures (1us, 1ms, 100ms, 1s, 10s), taking three frames at each exposure time. The camera was cooled to -15C.

In order to verify that the problem is not USB port/cable, computer, or DC-201 power supply, I ran the exact same sequence of exposures on an 8L camera. The only difference in the configuration was the offset, which was set to 115 instead of the 123 that was used on the 10 camera.

Attached are two frames, one each from the two cameras. I chose to share only the 1 millisecond exposure images. These were debayered (RGGB for the 10, and GBRG for the 8L), then auto-stretched using STF in PixInsight, then saved as highly compressed jpegs. Ignore the focus, as the Canon lens has an electronic focus that is not functional when I connect to the QHY cameras. The important thing I was looking at was increase in brightness as exposure increased, as well as decent color balance, and finally proper progression of under to over exposure. With the 8L this happens as expected, but with the 10 it almost appears to not respond to the configuration settings.

Any idea what might be the problem? In this controlled experiment, the only difference was the cameras (and only a small change in offset setting between the two).

Al

Re: QHY10 strange behavior
« Reply #1 on: October 11, 2019, 08:33:28 pm »
Can you send me the FIT format of this QHY10-C picture? This helps me make a judgment.

Re: QHY10 strange behavior
« Reply #2 on: October 12, 2019, 11:50:25 am »
Can you send me the FIT format of this QHY10-C picture? This helps me make a judgment.

Hi llsong,

I've sent you a PM with a link to access the images from my testing.

Al