Issue with QHY168C

[brentbos]

I have always had this issue with my QHY168C and SharpCap but its more of problem now that I want to use dithering. Anytime I change the exposure or gain, Sharpcap will always count down to negative times before capturing the first frame after the change. For example, if I am doing a 4:00 capture, instead acquiring the first frame when it counts down to 0, I don't get the first frame until -4:00. This has always been a problem, but now that I want to dither and check the option to use a shorter exposure after a dither movement, my first frame it taking double the time to capture again. I believe I read once to try "Force Still Mode", but this crashes Sharpcap - every time. I'm current using 3.2.6396.0 but this is been a problem with every version I've used in the past year.

[admin]

Hi,

it sounds like the first frame after the changes going missing – that leads to the negative countdown – SharpCap is indicating that the frame is overdue as far as is it concerned. My first suggestion would have been to try the still mode option, so it's a shame that that crashes SharpCap for you I've seen similar reports from other people recently of the problem was still mode in the QHY cameras. It may be worth switching to the other version of SharpCap (use the 64 bit version if you currently have a 32 bit version or vice versa) - I've seen some reports that bugs that occur in one of them may not be present in the other.

Unfortunately there's only a limited amount of help I can give because the bugs that we are trying to deal with are in the QHY SDK software as far as I can tell – the best thing to do is to report those bugs to QHY as they will need to fix them.

Cheers, Robin

[brentbos]

Thanks for the reply. I just sent the error report for the crash in regards to "Force Still Mode". The issue (losing first frame and crash with "Force Still Mode" is identical with both 32bit and 64bit versions. Whether it's a problem with the QHY SDK or not, I don't know. I do know everything works fine with my QHY168C in both NINA and APT - I never lose the first frame. I also have a ZWO ASI224MC and it works with SharpCap - I never lose the first frame. I have tried two different computers, and multiple USB cables including a externally powered one. I also have the latest QHY drivers installed. It is just the first frame it has the problem with, after that if I don't touch the exposure/gain it will run perfectly all night. Although annoying it was a problem I could live with until starting with dithering.

[admin]

Hi,

I can see from your log that you are running the camera in RGB mode, which is a bit of an odd thing to do for deep sky imaging. I'd certainly suggest trying switching to RAW16 mode to see if that helps (also you will get more faint detail out of the camera that way). I wonder if still mode isn't designed to be used in RGB mode to be honest.

In the bug reports you've submitted the QHY code is trying to write too much data into the memory that SharpCap gives it for the frame data - the frame is 4952x3288 pixels * 3 bytes per pixel (total 48846528 bytes) and the QHY code is trying to write at least 48876234 bytes

Hope this helps,

Robin

[brentbos]

Argghh!!! You are right, I missed that it got flipped to RGB. With RAW16 "Force Still Mode" works fine and I no longer miss the first frame. Thanks so much.

[admin]

Hi,

thanks for confirming – I think I am going to change the code to disallow still mode when RGB is selected.

Cheers, Robin