Target shifting position in frame

[Wolfie6020]

Hi Robin.

I have been using Sharpcap for several years with no real issues.

My main use is for Solar and Lunar time-lapse captures over several hours.

After the latest update I notice the target will jump position in the frame occasionally while the guide scope using "LuSol Guide" remains nicely centered and guiding accurately within one pixel.

See attached two consecutive captures this morning of the Sun.

After stopping the capture - changing the capture area to another value then back to the original the Sun was centered again and I continued the timelapse.

This has only occurred with the last SharpCap update (I am on the 3.0.0.8 ZWO driver )

[Wolfie6020]

A follow up after a bit of experimenting.

I was able to replicate the problem by turning up the Turbo USB to 100% and 4 frames per second capture.

Here is a video demonstrating it in real-time.

https://www.youtube.com/watch?v=sbsz8TrSrB0

I have also included a corrupt frame that occurred in yesterday's timelapse that shows two images of the moon with horizontal lines.

Camera is a ZWO 183 MC (not cooled version)
Second camera on the Guide scope is a 120 mm mini
I also have an Ioptron mount using a third USB port on the Laptop.

This combination has been used dozens of times previously with no issues prior to the last Sharpcap update.

[admin]

Hi,

So, the very latest version of SharpCap 3.2 (3.2.6346) did include an update to the ZWO provided software. It certainly plausible that this update may have caused the problem you're seeing.

If the problem only occurs at all at 100% Turbo USB setting then I would just advise turning that setting down a little to get a stable image – that's basically the whole point of that particular setting – to give you the opportunity to turn up the performance as far as your system will handle or turn it down if necessary to give stability. There's no guarantee from ZWO that every camera on every computer will work perfectly at every possible value of that setting.

If you wanted to dig into this further then I think if you can demonstrate that the hundred percent value works perfectly with the previous version of SharpCap then you might have some luck raising the problem with ZWO.

Cheers, Robin

[Wolfie6020]

Thanks Robin.

I suspected it might be something with the updated ZWO software as I have hundreds of thousands of frames without a glitch on previous versions with the Auto setting for Turbo USB - using several different cameras.

I have posted a similar thread on the ZWO forums so we will see if they can shed some additional light.

Kind regards.

Rob.

[Wolfie6020]

On a positive note - after setting Turbo USB to 50 I have not had a single glitch in over 40,000 frames taken since my last post. (All day and all night time lapse at 1 frame per 2 seconds.

[admin]

Hi,

Glad to hear you have it working – at that exposure there's no need for high Turbo USB settings. I do recall that there was once a problem with USB2 ZWO cameras that the image after a dropped frame could be damaged in a similar way to the problems you are seeing. I actually had some code in SharpCap that gave an extra option to try to filter out these images, but that option only appears for USB2 cameras. If you are getting a dropped frame before every split frame then maybe is the same problem.

Cheers, Robin