First image won't update when capturing.

[glauria]

Robin,

I'm having a problem when I start a live stack where the first image never displays and I have to wait for the second one. In an effort to better explain the problem, on the bottom right corner of the screen, which says "Frame", it tells how far along the exposure is going until it's completed. In my case, I'm taking 3min exposures, and when the exposure starts, I'll see a bar which gives a visual indicator on how far along the exposure is progressing and there are two times given: one that counts up to 3min and one that counts from 3min down to 0sec.

What happens is, for the first frame, when it reaches the 3min mark, the bar becomes fully orange (in dark mode), and past the 3min mark, it will just keep going (with the orange bar staying solid) to 3:01, 3:02, 3:03. etc... but time that counts down, turns negative and reads, -0.01, -0.02, -0.03 until it gets to -3:00. After the second round, which has now taken 6 minutes of time, then the count will start over, (0:00/3:00 for the exposure time indicator ), the bar resets (turns black again) and the image will finally be displayed. This also happens for 1min exposures. The frustrating thing is that it takes 6min to get my first image which kind of stinks. I'd hate to go to 5min or longer exposures knowing that the first one is not going to load and that it's going to take twice as long to get my first image. From then on, things seem to work fine.

I checked the memory, and it looks fine, and the computer is pretty new. It's an Intel i7 processor running Windows 11. I tried messing with the USB traffic setting, but that doesn't help either. Right now, I have it all the way to 60.

Any ideas on why the first image isn't loading? Did I miss something in the USB troubleshooting guide?
Thanks,
-Gene

P.S. The camera that I'm using is a QHY168C.

[admin]

Hi Gene,

the first suggestion for this problem is to set the 'Force Still Mode' option in the controls on the right to on. This ought to help with the missing first frame problem, which tends to be an issue with some QHY cameras when used in long exposures in live mode. I have raised this issue with QHY, but no fix from them yet, so the still mode option is the best workaround that I am aware of.

cheers,

Robin

[glauria]

Thank-you very much Robin,

Sorry if this might be a common issue with QHY cameras that I didn't know about. It's been really annoying and it's one of the reasons why I bought a new computer for my observing (not that I don't regret doing it any way). I hope that QHY will come up with a fix to the problem. I'll keep an eye out in the updates with the hope that QHY will respond to solve the issue.

Clear skies,
-Gene

[admin]

Hi Gene,

yes, this one is annoying - it only affects some models (not any of the ones I have, so I can't even try to find a workaround). There are also technical reasons for the QHY cameras that I cannot auto switch the camera into still mode for longer exposures as I do for other brands - the problem is that again for some models of QHY camera, the resolution changes a bit between live and still mode, which would be a real problem if it happened when you changed exposure!

Sorry to hear that you have spent a long time chasing this issue

cheers,

Robin

[glauria]

My luck Robin,

I have to end up having one of those problematic cameras! If it might help, I will also be more than happy to let QHY know about the problem. Perhaps they might pay more attention about it if this issue came from one of their customers as well. I suspect though that they will probably tell me "Sorry" because they don't make this model anymore. If this is an issue with other models that are still being made, please let me know because that might still motivate them to do something about it.

-Gene

[Jean-Francois]

Hello,

Yesterday evening I did other tests with a different computer (fist test was with W11, yesterday with W10) and with different cameras (second QHY174, QHY268 and old QHY5-II).

The QHY268 or the QHY5-II was working correctly in Live and Still mode and both modes with the Live Stack.

It was not the case with the QHY174 camera.
The Live view was working properly (alone or with the Live Stack), but not the Still mode.

That is more than annoying ... ideally is to have the camera in Still mode for long integration time.
For each capture, the camera/SharpCap takes 2 images.
So for 20 seconds individual exposure ... 20 s capture followed by again 20 s capture.
I did not think to check which image is showed (the first or second capture).

The point is ... I think that is a "new" problem.
I did in the past several time deep sky imaging with the QHY174 camera and my Newton and I did not remember to have these problems with the camera.

Regards,
Jean-Francois

[admin]

Hi folks,

as far as I am aware, the problem affects a number of different models - there are various reports in the 'QHY cameras' forum on here. I don't have a list to hand unfortunately.

I last updated the QHY SDK in March, adding an update published in January. If you go back to SharpCap 4.1.11961 then you will have the previous SDK which may undo the issue that Jean-Francois is seeing.

I've just checked today and there is another new version available now, which I will try to include in the next SharpCap update. You can of course try downloading it yourself and copy the QHYCCD.dll files across if you feel comfortable with that sort of thing - see https://www.qhyccd.com/html/prepub/log_ ... !log_en.md

cheers,

Robin

[glauria]

I still have an older version Sharpcap installed on my old computer. I'll check which version it is and if it's a later version than 4.1.11961, I'll reinstall it with the version that Robin is suggesting. I'll even try V3 and see if the issue is still there.

-Gene

[Jean-Francois]

Hello Robin,

Thanks for the information.
I downloaded the dll and copy it in the SharpCap folder.

It works a little bit better.

The continuous double exposure disappears ... but not for the first image after a change from Live to Still mode.

But, I remark a strange behaviour ... Can you confirm it with your QHY174 camera ?

The USB Traffic has an effect.
With USB Traffic = 0 : problem with the additional exposure.
With USB Traffic = 1 or larger: no problem. That is weird.

But, I remark an annoying think when I change Live to Still mode and back ...
Not all the Camera Settings remain between the Still and the Live mode.
I change the USB Traffic on Live mode, but the USB Traffic in Still mode in not changed.
Only if "Enter" or the mouse is clicked in other input text field. (the mouse moved or click on the image is not sufficient)
The same with the exposure ... Is that "a feature or a bug" ?


Regards,
Jean-Francois

[admin]

Hi Jean-Francois,

I've just tested with my 174M and with the January QHY SDK (currently in SharpCap), almost all still frame captures seem to take twice as long as they should. Now and then one frame will go through in the correct time, or just a few seconds more than the correct time, but otherwise double time taken.

The new March version of the SDK seems to fix this issue, but as you have spotted the USB speed goest to zero when swapping from live <=> still mode - which didn't happen in the older SDK. I'm not having an issue at zero USB speed, but I will see what I can do to preserve the value across a live/still swap to avoid the problem happening for others.

I do wish we didn't keep having these new bugs introduced with SDK updates - unfortunately if I stopped updating the SDK regularly, new model camersa just wouldn't work, so I can't do that, but still...

cheers,

Robin