My purpose in re-shooting M16 was to capture the relatively dim nebulosity above the main cavity which seems to flow down to an arrow shape pointing at the Pillars of Creation. I also wanted to take advantage of good seeing and a smaller image scale than I've had in the past. This was shot binned 2x2 at 0.6" scale. Since M16 stays well below 40 degrees altitude at my site there was no need to try to eke out the last bit of resolution by using 1x1 binning.
As it turned out, this dim emission glow was quite dim indeed. And I needed the the SII channel to carry its weight since I used a dynamic Pixelmath blend using both SII and Ha in the Red channel. To balance the very bright bottom and dim top, I did two vastly different stretches of the Ha data. These were combined with a mask in Photoshop and used for the Luminance channel.
Color comes from the dynamic mix but I wanted the Ha/SII regions to present more as red than orange. So I also did an HOO mix and blended that partially in the red areas. This also helped with color noise since the Ha is much stronger than the SII.
Sharpening and Deconvolution were focused on the bright core only. Noise reduction was masked to only the shadows using a luminance mask that was adjusted with Levels in PS.
Stars were removed for the noise reduction, sharpening and some color adjustments. Starnet was used to identify the star locations and Content aware fill was used in PS to do the star replacement. Afterward, of course, the stars were replaced!
I've decided to present this as a somewhat cropped vertical to best give the feel of the nebulosity pointing down at the Pillars. But I'll upload my original framing - let me know if you prefer that. I'm 55/45 for the vertical at the moment
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