Sh2-106
Click image for full size version
February 10, 2026
Sh2-106 is a bipolar emission nebula and star-forming region in Cygnus, about 2,000 light years away. A star at the centre with a mass 15 times the Sun’s is blowing out the two lobes. That star is also causing the surrounding gases to glow. Sh2-106 doesn’t seem to be a very popular target. That’s probably due to its small size and proximity to bigger and brighter targets, like the Crescent Nebula. In addition to the natural-colour image above, I created a Hubble palette version. Click the thumbnail below to see the full-resolution version.
Tekkies:
Acquisition, focusing, and control of Paramount MX mount with N.I.N.A., TheSkyX. Guiding with PHD2. Primalucelab low-profile 2″ Essato focuser, ARCO rotator and Giotto flat panel. Equipment control with PrimaLuce Labs Eagle 4 Pro computer. All pre-processing and processing in PixInsight. Acquired from my SkyShed in Guelph. Average transparency and seeing. Acquired under a waxing crescent moon from July 4 – August 11, 2025. I captured the broadband data when the moon was less intrusive.
Celestron 14″ EDGE HD telescope at f/11 (3,931 mm focal length) and QHY600M-SBFL camera binned 2×2 with Optolong filters.
23 x 5m Red = 1hr 55m
21 x 5m Green = 1hr 45m
21 x 5m Blue = 1hr45m
79 x 5m S2 = 6hr 35m
79 x 5m Ha = 6hr 35m
74 x 5m O3 = 6hr 10m
Total: 24hr 45m
Preprocessing: The WeightedBatchPreProcessing script was used to perform calibration, cosmetic correction, weighting, registration, local normalization, integration, Drizzle integration, auto-cropping and plate solving.
Colour master: A colour master was made from the Red, Green and Blue masters using ChannelCombination in RGB mode.
Gradient Removal: DynamicBackgroundExtraction was applied to the RGB and narrowband masters.
Colour Calibration: ColorCalibration was used to calibrate the RGB master.
Deconvolution: BlurXterminator was used on the RGB and narrowband masters with Automatic psf at default settings.
Linear Noise Reduction: NoiseXterminator was applied to the RGB and narrowband masters with settings Amount=0.9 and Iterations=3
Star Removal: StarXterminator was used to remove the stars from each of the RGB and narrowband masters, with default settings. Only the RGB stars-only image was preserved.
Hubble Palette Image Creation: The three narrowband masters were combined using ChannelCombination in RGB mode assigning S to red, H to green, and O to blue.
Stretching: MultiscaleAdaptiveStretch was applied to the RGB and SHO masters to make pleasing images. Approximate background level after the stretches was 0.10.
Nonlinear Processing
Background Cleanup: Artifacts that were visible in the three master colour images were removed using the CloneStamp tool.
Nonlinear Noise Reduction: NoiseXterminator was used to reduce noise in the background areas of the RGB, Hubble and OHS masters with settings Amount=0.9 and Iterations = 3
Narrowband Enhancement of RGB: The CIE L* channel was extracted from the SHO image using ChannelExtraction in the L*a*b* colour space. The CreateHDRImage script was used to combine the narrowband lightness with the RGB.
Dynamic Range Compression: The CreateHDRImage script was used to compress the core of the nebula using a mask made with the RangeSelection tool. This was applied to all three images.
Contrast Enhancement: LocalHistogramEqualization was applied twice to each image. A Contrast Limit of 1.5 and 1 iteration was used for each LHE application (scale 150, strength 0.35; scale 50, strength 0.22).
Sharpening: A mask was used to select brighter regions of nebulosity in each image for sharpening with MultiscaleMedianTransform (Layers 2 – 43with strengths of 0.07, 0.05 , 0.03 and 0.03, respectively).
Hubble Palette Colour Adjustments: CurvesTransformation was used with the Hue tool to adjust the colour tones in the two narrowband images. The SelectiveColorCorrection script was also applied to adjust colours.
Star Processing and Restoration: HistogramTransformation was used to stretch the stars-only RGB image, followed by CurvesTransformation through a star mask to boost saturation using the Saturation slider. The stars were added back into both master images using the PixelMath expression combine(starless, stars, op_screen()). The Cosmic Photons Star Reduction script was used to slighlty reduce the stars.
Final Steps: Background, nebula and star brightness, contrast and saturation were adjusted using several iterations of CurvesTransformation, with masks, as required. ICCProfileTransformation (sRGB IEC61966-2.1; Relative Colorimetric with black point compensation) was applied prior to saving as a jpg.
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