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Quite a good result. A lot of blue stars, is that accurate?
Well, look who's gone over to the dark side eh?
A good break there with the adapters working out, it looks nice and solid and square.
As far as gain goes for the ASI183mm Pro I have followed threads on CloudyNights about best settings and you are right there are lots of opinions.
What I found from Jon Rista and 2nded by Ben on this forum was gain 53 for LRGB and gain 111 for narrowband and 300 seconds for each.
I have also used 10mins for narrowband as well and I think I will make that standard. 10 minutes for LRGB though gives oversaturated stars on the Honders.
QHY uses a different scale but its a guide.
As far as offset goes all that does, if I understand it correctly, is shift the black point of the histogram much like levels and curves in Photoshop. So not a real important thing to touch as far as I can see. In fact the ASI driver for the Sky X just has gain as the variable there is no entry for the offset (the simpler the better).
On the 183mm I am finding 300 seconds gain 53 -10C works well and 300-600 seconds gain 111 -10C for narrowband. 60 seconds would be a pain to process but perhaps it works better. Read noise is lower with higher gain so there is a guiding principle. Dynamic range also falls with higher gain so there is the counter principle.
A lot of LRGB and Ha and O111 subs show almost no amp glow as the signal is so strong but S11 shows lots.
As you say it calibrates out well although it can on worst case leave some remaining slight noise.
I would up the gain or exposure for S11, probably simply the exposure as shifting gain in a sequence of shots is not available in the Sky X driver.
As to oversaturating wells, at 15,000 its not that different to the ICX694 CCD and I am getting nicer looking stars than I ever got with that CCD.
As far as pattern noise goes, again I find if the exposure is long enough that pattern noise is swamped by signal and it disappears. The balance between that and oversaturating pixels is the key and that would vary with aperture and F ratio.
Greg.
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