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M33, Vixen 81s + Atik 314E, LRGB filters

Posted: Wed Oct 02, 2019 1:42 pm
by turfpit
M33 Triangulum Galaxy. Vixen 81s + Atik 314E + Teleskop LRGB filters and filter drawer. SharpCap + FITS Liberator + Siril + Gimp. Bortle 6. Unguided.
L: 48x120s bin 1x1
R: 21X90s bin 2x2; G: 12x90s bin 2x2; B: 19x90s bin 2x2
100 flats for each filter, 100 bias bin 1x1, 100 bias bin 2x2, 15 darks bin 1x1, 15 darks bin 2x2.
Total LRGB integration time 2.4 hours + 1 hour capture for bias, flats & darks.
Stacked L40, R17, G10, B16 to achieve colour balance, see https://u235.herokuapp.com/#color-balance-instructions by Brian (@oopfan).
RGB Composite process carried out in Siril.

M33-L40-R17-G10-B16.jpg
M33-L40-R17-G10-B16.jpg (147.35 KiB) Viewed 661 times


A bit noisy, I reckon this object needs more data and/or darker skies. I think I will capture a whole new set of darks on a cloudy night, say 50 of each, and re-process.

Dave

Re: M33, Vixen 81s + Atik 314E, LRGB filters

Posted: Fri Oct 04, 2019 3:54 pm
by mAnKiNd
Very interesting and really nice result!

I wonder what the colour balance would look like without the luminance layer (at the expense of SNR), as I always find that when I integrate luminance on emission nebula RGB, it pushes my data towards "Salmon City Pink"! :s

Very interesting read from Brian as well, and although unrelated to the present post, this particular source:

http://www.astrosurf.com/buil/CMOSvsCCD/index.html

...argues a different QE profile to the IMX290 sensor (the only measured QE I could find on this sensor), which I own and use and have anecdotally observed similar results in agreement with astrosurf, than what Brian states..I'm sure he can chime in here and share his thoughts :)

Cheers Dave and keep em coming!

Minos

Re: M33, Vixen 81s + Atik 314E, LRGB filters

Posted: Fri Oct 11, 2019 8:51 pm
by turfpit
Thanks Minos. I tried the RGB only - I see what you mean re the red influence.

Here is the RGB only:

M33-RGB-only.jpg
M33-RGB-only.jpg (70.4 KiB) Viewed 517 times


and the histogram straight after RGB composition:

histogram.JPG
histogram.JPG (39.81 KiB) Viewed 517 times


The link was a heavy read.

Dave

Re: M33, Vixen 81s + Atik 314E, LRGB filters

Posted: Wed Oct 23, 2019 12:33 pm
by mAnKiNd
Nice one Dave :)