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oska
16-10-2022, 09:11 PM
Just for fun on a poor seeing night, 3rd Oct - 1/4 moon, heavy dew & patchy clouds. I figured I'd have a little fun. I tried a range of gain values and let NINA's exposure calculator guide me on exposure, basically 3-5 times recommended.

These are all experiments and no effort was made to "get" an image, basically to see what all the fuss was about, and now I see :lol:

ASI1600MC-c calibrated with darks, flats & dark flats.
Unity gain for reference is 139. 300 is considered the max

Cat's Paw: 45mins of 15s @ 350g (Zwo dual band filter) the moon was shining almost right down the scope :/
Sculptor Galaxy: 45mins of 10s @ 250g (UV/IR cut)
The Great Barred Spiral Galaxy: 44mins of 30s @ 350g (UV/IR cut)
Triangulum Galaxy: 17mins of 10s @ 350g (UV/IR cut)
Andromeda: 8mins of 10s @ 300g (UV/IR cut)

There is some indication in the file names as to how I tortured them in PI.
Mostly Photometric Colour Calibration, Dynamic Background extraction x2 division & subtraction, ez Denoise, ez Soft Stretch and a little contrast and saturation curve.

xelasnave
17-10-2022, 07:16 AM
You are doing great..you just need to put more time in:lol:
Alex

oska
17-10-2022, 09:22 AM
Thanks Alex. I realise they all need at least double or 10 times the data but I found it very interesting that the result from essentially injecting significant noise into the signal and then averaging or oversampling(?) it to get the detail out. Fascinating. Kinda, at least conceptually if not mathematically, like drizzle, kinda.
It was a technique I learned about when designing process control systems in the early 90's where you could get higher effective resolution data by averaging a deliberately noisy signal. Exactly like stacking.
It really was one of those "I should have packed it up hours ago" type nights.

Dave882
17-10-2022, 10:40 AM
Very nice results for the integration times- especially ngc253 and m33. Keep experimenting and having fun- that’s what this hobby is all about!!

oska
17-10-2022, 11:13 AM
Thanks Dave, they were definitely the standouts in the "OMG look at that!" kinda way. And thanks for the lofty heights to aim for ;)