I don’t usually repost the same data under a new heading, but after seeing how the Starizona HαRRGB methods worked on M17 I had to go back and try them on M16. These data look (in my opinion) dramatically better when processed using the Starizona methods so I’m going to break my own rule. I used my RGB image posted previously (https://astrob.in/352634/B/), added Hα to the R, and used either Hα+R (method 1) or Hα alone (method 2) for luminance. I tweaked the curves as suggested on the Starizona site, boosted the saturation a little, and used Carboni’s layer-masked “less crunchy more fuzzy” to make the stars less harsh. I think these look a lot better than what I posted earlier. This time I think I prefer the method 2 image for the detail it reveals in the nebulosity.

Date: 15-20 Jun 2018

Subject: M16, Eagle or Star Queen Nebula

Scope: AT8IN+High Point Scientific Coma Corrector

Filters: ZWO 31 mm diameter unmounted L, R, G, B, Hα

Mount: EQ-6 (EQMOD 2.000j)+PEC

Guiding: Orion Thin Off-axis Guider + DSI IIc +PHD 2.6.5 (Win 10 ASCOM)

Camera: ASI1600MM-Cool, -20 °C, Gain 139 Offset 21

Acquisition: Sequence Generator Pro 3.0.2.91

Exposure: 51x180 L, 20x180 R, 20x180 G, 20x180 B, 48x300 Hα

Stacking: Deep Sky Stacker 4.1.1 (64-bit) dark+flat+bias, κ-σ stacking with κ = 1.5.

Processing: StarTools 1.4.332: Combined R, G, and B in StarTools. Binned 2x2, cropped, wiped, developed, HDR, color, deconvolution. Stopped tracking to smooth. Binned L 2x2, cropped, no wipe, and developed followed by HDR. Deconvolution followed by untrack smoothing. Combined L with RGB in Photoshop. Used some layer-masked saturation adjustments, both in the master and in the red channel, to try and retain the red color. A little of Carboni’s Astronomy Tools’ increase star color followed by less crunchy more fuzzy. Green cast in stars removed using StarTools’ “Cap Green to Yellow”. Also some different choices in Curves for the luminance and RGB layers to better bring out the reds in the emission nebula. Added Hα as described above.