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More or less I am aiming at as close as I can get to 1 photon equals 1 electron equals one step in the ADC conversion (Too simplistic I know given I am ignoring QE completely there, I should call it as I did above, 1 converted photon)
I was thinking of doing some focus tests to see if I can defocus the red and green and get better blue focus. Even with the ASI294 if that is workable, with sufficient time invested in shooting and processing I can achieve similar by splitting out the channels to separate FITS files in APP then recombine the separately focused blue files with the normally focused red and green. I will have to fire up APT again and see if I can kill the red and green channels in the preview (Given APT debayers the image preview) and if I can work out a good focus offset from the normal and tighten the blue up in separate subs just to extract the blue channel from then it would hopefully indicate that the scope would work OK with a mono cam.
I am glad you mention the RGB filters being UV/IR cut, I had not tracked that bit of info down yet and I take the "Typical passband" pics on websites as marketing guff more than anything else. I do wonder what the passband of the ZWO red is, the RGB sample data I downloaded included something that was considered to be an artifact on a similar image in the Malins this year but I have worked out they are stars that are very rich in red (And presumably NIR) and almost invisible in the green data and totally absent in the blue, so in the final integration they show up as bright red stars and look like processing artefacts, miss-registered stars or similar. I had an image shot with my cam of the same target with the UV-IR filter and the ASI294 and they were not visible at all on my shot.
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