Cygnus Wall 2 ways (Tim Hutchison)

Cygnus Wall 2 ways

I recently shot H S O R G and B filters on the Cygnus wall. The first image is an SHO representation of the area. In the second, I combined the narrow band filters with a new process I have been playing with where I attempt to assign the true color (as close as you can get in an sRGB color space) to each of the NB filters, then overlay the RGB stars. I account for the quantum efficiency of the camera in each of the channels as well. The images are combined as linear images, then stretched. My formulae look like this:

Red: max(.2196*S/qes, .4510*H/qeh, .0078*O/qeo)
Green: max(0 * S/qes, .0039*H/qeh, .9961*O/qeo)
Blue: max(.0431*S/qes, .1216*H/qeh, .8275*O/qeo)

where:
H = Ha image
S = Sii image
O = Oiii image
qeh = Quantum efficiency for 656nm
qes = Quantum efficiency for 672nm
qeo = Quantum efficiency for 501nm

The numbers come from an RGB representation of the 656, 672, and 501 nm spectral colors. This is as close as I could get to the real colors. sRGB is not broad enough to actually represent these spectral colors, but these are as close as I can get...

I still like the way that SHO looks, but I would be very interested in your opinions on the appearance of the "natural" looking image. I have placed in in the mouseover so that it is easy to compare.

****************
Edit:
After a few tweaks to the process I have uploaded my (probably) final revision in what I am calling my "True(er) narrowband palette". While it isn't really the true color of the narrow band emissions (and can never be with current monitor technology) I think this comes pretty close and is a pleasing, natural looking image.

Original
B
Final
C

B

Title: Attempt at Natural colors for H, S, and O

Uploaded: ...

Narrowband imaging
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Status	Advanced success
Started	...
Astrometry.net job	6313861
PixInsight job	AOGEOFLPZ10QVSO2TYMP0UETWXR931MQ
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RA (center)	20h59m53s.976
RA (top/left)	21h02m36s.239
RA (top/right)	20h57m19s.624
RA (bottom/right)	20h57m13s.671
RA (bottom/left)	21h02m26s.433

Dec (center)	+43°40′00″.21
Dec (top/left)	+44°01′44″.89
Dec (top/right)	+44°03′32″.44
Dec (bottom/right)	+43°18′00″.58
Dec (bottom/left)	+43°16′13″.71

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