QHY168c stacking problem

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mihai_mail_ro
Posts: 7
Joined: Fri Apr 25, 2025 3:14 pm

QHY168c stacking problem

#1

Post by mihai_mail_ro »

I have a new (for me) QHY168c camera and I see some strange behavior in regard to stacking looping as for certain exposure times the loop is frozen in Live view mode.

I have seen the longer exposures more problematic (5 minutes exposures are frozen at first exposure) but also shorter ones (at 4 sec. the loop is not frozen but some exposures are longer than the 4 sec settings). The behavior is random and I have tried to change several parameters (DDR on/off, gain value, offset, USB buffer, etc).
I have also tried to run sensor analysis and the error I got after some tests is "measurement fail" and " "cannot set exposure at desired value".
I have also changed the cable and the USB port (all are 3.0 at Lenovo Legion gaming laptop).
Then I have changed the drivers, first ASCOM and then replaced native latest stable version with December 2024 version.
I see some slight improvement with ASCOM but there are certain exposure values when loop is again frozen.
Finally, after 4 hours of testing, I have changed to NINA (which I am not used to) and here the things looks better, up to now no frozen loop experienced, even at 10 minutes stacking exposure running for 90 minutes now.

Here an example where the exposure is longer than the preset duration.
WhatsApp Image 2025-04-25 at 17.28.23(1).jpg
WhatsApp Image 2025-04-25 at 17.28.23(1).jpg (247.65 KiB) Viewed 512 times
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admin
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Re: QHY168c stacking problem

#2

Post by admin »

Hi,

if you see this sort of problem with a QHY camera, then the best thing to try is to set 'Force Still Mode' to on - this makes SharpCap run the camera in still mode rather than video mode, which is much more reliable for longer exposures.

For a lot of brands of cameras, SharpCap can make this switch automatically as the exposure is changed, but unfortunately some QHY cameras use slightly different resolutions for video vs still mode, which makes the automatic changeover impossible.

hope this helps,

Robin
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mihai_mail_ro
Posts: 7
Joined: Fri Apr 25, 2025 3:14 pm

Re: QHY168c stacking problem

#3

Post by mihai_mail_ro »

Thank you very much Robin, this is probably the best explanation for this strange behavior.
I have run just couple of tests for long exposures and till now it looks good.
If I change the exposure to lower values (<30 sec) the Live view mode is fine but for longer exposures the Live view loop is not working fine.
Now I have disabled Live view mode and doing stacking only.

Best regards
Mihai
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