Sky Brightness Measure hangs

[AstroDave]

Hi

I'm a new user excited at the prospect of getting some good advise from the smart histogram function (I'm a licensed Pro user) . However I've never been able to get it to work. I have successfully completed the Sensor Analysis (and navigated the its-too-dim-or-its-too-bright issue), but when I press the Measure button I never get a result. It does change the exposure to 1000ms and sometimes it changes it to >5minutes, but then it just sits there. I have waited sometimes up to 20 mins to no avail. I have run it on full frames and on on an FX Selection Area - all to no avail.

All other functionality has worked fine: Polar Alignment, Capture, Live Stacking. But Measure sky brightness and I get a
"Fetching still frame from ZWO camera failed with ExpFailed" in the log.

Vers: 3.2.5892.0
Camera: ZWO ASI294MC Pro
Scope: LX200 8" (with FR)
OS: Win 10 Pro build: 18363.657
Log extracts attached

Any ideas?

Regards

[admin]

Hi,

What happens if you try changing the camera exposure manually to longer intervals like 2s or 5s? Does that work? From the log it looks like exposures of 2 to 3 seconds (the value in the log is in milliseconds) are failing when the sensor analysis attempts them - I don't think there's any reason that that should be any different from the results if you just set the exposure slider to a similar length of time.

I would certainly recommend anyway that you have a look at the USB troubleshooting steps at the top of the bug reports forum page – there are some good suggestions in there which can sometimes help unblock this sort of issue.

Cheers, Robin

[AstroDave]

Thanks for the reply

I’ve had no trouble at all with longer exposures, 5s,10s,40s,2mins for example.

Thanks for the advise on USB troubleshooting - I will work through that document.

Regards

[AstroDave]

OK. It is a USB issue. Replacing the USB cable with a 1 metre one allows the measure to complete.

Thanks very much for the advice.

[admin]

Hi,

It's amazing how sensitive some of these cameras are to USB cable length – we have all become used to USB stuff just working, but these high speed high resolution cameras push the USB system to its limits. I found that 3 to 3.5 m of cable is the maximum that will work at all reliably for USB3.


Cheers, Robin