Sharpless 173 aka Sh2-173 in Cassiopeia - HaRGB

Sh2-173 HaRGB

Sharpless 173 is the large faint red nebula in Cassiopeia..

12/14/14 x 10 min each of RGB, 35x20min H-Alpha
Camera: Apogee U16M (16803) w Gen II Astrodon RGB and H-Alpha
Scope: Planewave 12.5" CDK
Mount: Paramount ME
Guiding SBIG ST402ME via Astrodon MMOAG
RGB and H-Alpha processing in PixInsight; Blend of H-Alpha w RGB and save-for-web in PS CC
PixInsight RGB processing: CombineColours, SPCC, BlurX, NoiseX, Curves and HT followed by masked Satruation Boost via Curves, Save as TIFF
PixInsight H-Alpha processing: BlurX, NoiseX, StarX, Curves and HT then LHE then saved the starless H-Alpha as TIFF
Photoshop: Split channels, add starless Ha to Red at 100'% and to Blue at 20% using Lighten blend mode. Flatten then remerge them. Colour Balance and Selective colour layers. Save forWeb.

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H-Alpha channel - 12 hours (uncropped vs. the HaRGB)

Sh2-173 H-Alpha

Lucknow, Ontario
November 2022
HaRGB reprocessed Dec 2023