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I wrote a long reply and it didn't go through. Oh well here goes again.
I use gain 53 for broadband (LRGB) and Gain 111 for narrowband. Offset default at 8. Cooling to -10C or -25C.
I got these gain settings from John Rista's post on Cloudynights (a long thread about the 183mm) and from Lee on this site.
Exposure lengths are:
300 seconds for LRGB and 600 seconds for narrowband or for dim galaxies.
I also have tried 60 second exposure lengths for good colour RGB stars but yet to process images using that. Lee used 30 seconds for RGB stars in narrowband images and gets a great result.
I use 1x1 mostly but 2x2 for O111 and S11 and sometimes for RGB.
These cameras only use software binning so the gain is less than CCD.
111 is unity gain.
Amp glow dark subtracts out very cleanly so long as temperature, exposure length and gain are the same. Amp glow is also very weak on images with a bright object like M42 or M83. Even a 10 minute exposure of M83 shows hardly any amp glow. But a 10 minute exposure of NGC3521 shows a lot.
Don't use bias frames. Some use dark flats, I don't bother. These cameras are very clean and if not for the amp glow I would not bother with darks either.
These 2.4 micron small pixels behave a little differently to typical CCDs of 6-9 microns.
Firstly they are harder to focus. I find shifts in focus are smaller for the same change as on a CCD. It takes longer to focus.
The stars are rounder as more pixels are being used to display a star.
You can bin 2x2 and not lose hardly any resolution.
-10C should be achievable all year round as my camera on test cools to 47C below ambient.
-10C is very clean so deeper cooling has less than usual benefits. I am using -25C at the moment though as deeper cooling may also lower read noise and also reduces aritfacts. Not that the camera has any artifacts or lines etc. A very even and perfect sensor which makes sense as these sensors are from mirrorless and DSLR cameras.
Don't make it too complicated or it will become a mess of complication and difficult to process images.
Be careful with file naming, put the gain in the name of the file so you know what it was as CCDStack does not show what the gain used was.
I use The Sky X Pro and the ZWO Ascom X2 driver and it works very well, connects instantly and is very stable and robust. A big pus.
The camera is very light and small and outs no strain on the focuser or tracking.
The weakness of CMOS seems to be weak star colours. So watch that.
Also too long an exposure will blow out highlights more easily due to the small well sizes and the high sensitivity of these sensors. It will also result in all white star colours easily.
So shorter exposures are better and no 20 minute exposures unless you are doing dim narrowband.
QE is massive and still high in narrowband compared to CCD. Its past most CCDs by 40% or more.
Binning 2x2 could also be useful for the small file sizes and somewhat increased signal with very little loss of resolution.
The sensor is very small so field of view is limited so I use this sensor mostly for galaxy imaging or smaller nebulas at 1260mm focal length
(AP Honders Riccardi 305mm F3.8). It works well.
Small pixels also means more sensitive to seeing.
Greg.
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