Rebranded Touptek IMX571 OSC Fails Sensor Analysis

[SPZ56]

Hello All,

I received a new Touptek (rebranded) IMX571 OSC a few days ago. It works fine with 5m darks not showing any trace of amp noise (I have yet to test it on a scope because of uncooperative weather). There is one quirk that causes sensor analysis to fail. At exactly 201ms exposure, independent of gain setting, there is a shift in the output signal (see the attached plot). This appears to be some kind of built-in mode shift. I could not find any information on the purpose of the mode shift. The signal shift occurs in both LCG and HCG modes. Also, this does not appear on the mono version of this camera.

Questions:

1) What is the reason for the mode shift?
2) Any way around it so I can complete the sensor analysis?

Thanks,
Steve

IMX571C 2023-10-30 .jpg (54.98 KiB) Viewed 6539 times

[admin]

Hi Steve,

which version of SharpCap are you using and how are you accessing the ToupTek camera?

If you are using a recent SharpCap 4.1 then you might be using the 'advanced directshow' support for the cameras that gives near to full functionality via the DirectShow APIs. If that's the case, check you are on the very latest version as there have been improvements and fixes. You should also make sure you have the latest version of the ToupTek directshow drivers.

It's also possible that you might be using the ASCOM driver for the camera, in which case the version of SharpCap is less important but you should check that the ASCOM driver itself is up-to-date.

Both of those 'update if you can' suggestions are hopeful more than anything, since I haven't seen this sort of problem with a big shift in brightness at a particular exposure point before - the worst I have seen previously is some cameras where the exposure time isn't exact and works in 'steps' - i.e. the exposure you get is the one you ask for rounded to the nearest 0.1s - typically for exposures above 1s.

I do have some further improvements coming in ToupTek support within the next month or so, which may be sufficient to fix your problem - unfortunately they are not ready for release just yet.

cheers,

Robin

[SPZ56]

Hello Robin,

I used the ToupTek ASCOM driver in both SC4.0 and SC4.1. Both versions gave the same results with a signal transition at 201ms. As far I know, I'm using the latest ASCOM driver available from my camera supplier. I did notice the Advanced Directshow function in SC4.1 but I did not try it: I do not plan on using the camera with an 8 bit output.

I will wait for your further improvements regarding this camera. Thanks for the great application. SharpCap is my go-to program for just about anything involving a scope and an astro camera.

Regards,
Steve

[admin]

Hi Steve,

if you see the camera name appear in DirectShow cameras rather than just 'ToupCam', it's worth trying it - I have a workaround to allow 16 bit modes for the ToupTek cameras via the advanced directshow support. You also get cooler control, binning, etc.

cheers,

Robin

[SPZ56]

Hello Robin,

I should have tried the DirectShow driver before bothering you. The sensor analysis worked like a charm and the driver has most (if not all) of the functions I use. I am attaching a screen copy of the results in HCG mode.

Thanks for the help,
Steve

[admin]

Hi Steve,

glad that worked for you - clear skies!

Robin