Raw frames courtesy of Deep Sky West Remote Observatory in New Mexico, USA. (deepskywest.com) Data obtained with FSQ 106EDXiii / QSI683wsg / Lodestar / Paramount MyT.

Approx 26 hrs total integration (16x1800s O-III, 20x1800s S-II, and 16x1800s H-alpha). The palette is SOO with R = S=II, G = O-III, and B = O-III, and with H-alpha serving as Luminance.

This is really a bi-color image with H-alpha Luminance. The central region appears relatively starved of S-II and dominated by O-III. The choice here is what color to make O-III. By all rights it should be a greenish color at 501 nm. But we can stretch the color-space contrast, making it more blue.

At any rate, red areas are dominated by S-II, and blue/green areas by O-III. In truth, the whole nebula is hugely dominated by H-alpha and dust. S-II and O-III make up a much weaker component of the nebula. Everything out there is dominated by H-alpha. So for a change, let's not look directly at that.

Regions where both S-II and O-III are present become a whitish color, by analogy to tri-color image where all three component colors are present.

The fact that this nebula looks so bright implies that it must be extremely red in natural light. The lightness is being controlled by the H-alpha channel, which is much stronger than either the S-II or O-III lines.

This is interesting... I just did an SHO palette version, with 15% Ha in the G channel (NASA Hubble style). The image above is actually much more colorful in just two color components (S & O) than the tri-color SHO image. The SHO palette shows a bluish central region and a yellow border at the left. The image above contains more variation in the blue central region (sky blue, violet, white). Our image above also shows more faint detail in the outer reaches of the nebula. That was unexpected.

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Revision goes back to defensible color calibration, and incorporates best practices in PixInsight for bringing out nascent details.

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Rework to bring out more details.

One of the aspects I'm noticing about the SOO palette, here and in other SOO images (Pelican, Elephant Trunk, Heart), the bluish central area, highlighting the O-III line, appears very much like a pool of water, with features showing just below the surface, and sometimes rising through the surface with an abrupt color shift from below to above. Very interesting psychovisual effect. This effect does not seem as pronounced with the standard SHO and CFH palettes.