Sh2-115 in H-Alpha + OIII + RGB

Sh2-115 HaOIII+RGB


Sh2-115 aka Sharpless 115 is in Cygnus. The image above is done via the Foraxx palette script in PixInsight with the RGB overlaid (see below). Then tweaked in PS.

Here's a conventional blend done via Photoshop putting 100% Ha into Red and 15% into Blue plus 33% of OIII into each of Green and Blue - all via Lighten Blend Mode

Sh2-115_HaOIII+RGB_via_PS

and then the pure RGB for comparison 

Sh2-115_RGB

Here is the starless H-Alpha channel:

Sh2-115 H-Alpha (starless)

Scope: Planewave 12.5" CDK
Camera: Apogee U16M w Astrodon GenII H-Alpha filter
Mount: Paramount ME guided w Astrodon MMOAG and SBIG ST-402ME
RGB each 10/10/14 x 10min, H-Alpha 34 x 20min; OIII 19 x 20min
Acquired with TheSkyX and CCD-Commander

PixInsight Processing:
RGB: Combine Channels, SPCC, BlurX, NoiseX, StarX, Curves and HT on the starless RGB, Local Histogram Equalization (LHE), mild stretch of the stars (with saturation boost), stars-back-in via Pixel Math, Save-as-TIFF
H-Alpha and OIII: BlurX, NoiseX, StarX, HT and Curves, LHE, Save-as-TIFF
Foraxx script utility was used for the top version

Photoshop Processing:
Split RGB channels; added the Ha to Red at 100% and Blue at 15% using Lighten blend mode. Added the OIII to Green and Blue at 33% using Lighten blend mode. Boosted the Ha in the Red via Curves., Merge Channels, Selective Colour and Colour Balance adjustment layers, tidy up some stray satellite trails. Save for Web

Lucknow, Ontario
Augues 2025

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