QHYCCD

QHY294M-Pro single stripe imaging artifact in center of frame

QHY294M-Pro single stripe imaging artifact in center of frame
« on: February 07, 2021, 05:32:01 PM »
I noticed that my new QHY294M-Pro seems to produce an unusual single stripe artefact in the center of the image that it is clearly noticeable in my light frames. I have so far only taking images in one imaging session with this camera and operated the camera in the 11M mode. So far I found the artifact present in all frames that I reviewed. I suspect this could be some issue with  the imaging sensor and am kindly looking forward to your advise for next steps on how to handle this problem. Please see two attached examples to illustrate the problem.



Re: QHY294M-Pro single stripe imaging artifact in center of frame
« Reply #1 on: February 14, 2021, 05:10:15 PM »
Some further image analysis shows that the streak is a copy of a four-pixel-column which is offset by 14 pixels to the left. Attached image shows the result of a subtraction of the original frame with one that was obtained by shifting the original frame 14 pixel to the right, setting pixels with equal values in both frames to zero in the resulting frame. The stripe artifact is now revealed to stretch from the center of the frame all the way to the top row. With this method I am able to observe the issue also being present in any other frame taken with the camera including dark and bias frames where it's not apparent from just looking at the frame. Since the subtraction generates negative pixel values the intensity scale of the resulting frame was shifted back to unsigned 16bit grey scale values thus previous zero values now appear grey.


Re: QHY294M-Pro single stripe imaging artifact in center of frame
« Reply #2 on: February 21, 2021, 10:00:16 PM »
After some further testing it seems that I get this artifact only when imaging with SDK v20.12.27 (OSX/Linux). The artifact isn't present in images taken with SDK v21.02.01 or v21.02.11. I tried a couple times imaging with these three SDK versions and the problem reliably resurfaces each time I downgrade the SDK version back to v20.12.27.

Since I haven't heard back on this post yet, would you be able to confirm that this indeed is an SDK/firmware issue and not related to the camera?

Thanks much and kind regards
Niels

llsong

  • *****
  • 152
    • View Profile
    • Email
Re: QHY294M-Pro single stripe imaging artifact in center of frame
« Reply #3 on: February 22, 2021, 12:32:52 AM »
Hello

Regarding the ghosting problem you mentioned, you can update the latest Allinone installation package released by QHY. As for the single streak artifact you mentioned earlier, have you ever observed whether it is included in the dark field frame, can you send FITS format images? This helps us to determine whether the artifact comes from inside the CMOS chip.
https://www.qhyccd.com/file/repository/publish/AllInOne/210220/QHYCCD_Win_AllInOne.21.02.20.13.exe

Re: QHY294M-Pro single stripe imaging artifact in center of frame
« Reply #4 on: February 22, 2021, 03:21:46 PM »
Hello

Thanks much for the reply. Yes, the ghosting is also present in dark frames and bias frames (although hard to see without the image subtraction). It seems that there is another ghosting that occurs within the calibration area to the right of the frame. I think it's the same: 4 pixels wide and 14 pixels offset, running from the middle row all the way to the top of the frame. This is also visible in the subtraction image. Please find the FIT file for a sample dark which I recorded with EZCAP_QT and the original FIT files for the two light frames I had posted earlier for download under this link here:

https://www.dropbox.com/sh/pi6pe6meubt79sq/AACwgF5yEJWPxJISwo9ik-laa?dl=0

Let me know should the download not work for you.

Kind regards
Niels

llsong

  • *****
  • 152
    • View Profile
    • Email
Re: QHY294M-Pro single stripe imaging artifact in center of frame
« Reply #5 on: February 23, 2021, 05:08:21 AM »
Hello Niels

I have received your FIT format image. It depends on the CMOS chip, which may be an unrecoverable artifact caused by cosmic rays. We plan to replace one for you. Where are you? Can you tell me your address and email? I will arrange for a maintenance engineer to contact you for replacement。

Re: QHY294M-Pro single stripe imaging artifact in center of frame
« Reply #6 on: February 23, 2021, 08:22:44 AM »

Thanks much for your support on this topic.

You should be receiving my contact information with a separate email I sent out to your profile contact. Please let me know if this shouldn't have worked.

Kind regards
Niels