Decided to just shoot a semi-random part of Cygnus. The large extended Ha region in Cygnus is unofficially called Smaug, and this is a photo specifically of the area around LBN 325/326. The nebulosity in this pic is false color, but the stars are true color RGB. I really love how this turned out with the narrowband palette, especially with the Oiii region on the right side looking almost like a true color Ha region. Captured over a shitload of nights from Aug-Oct 2024 from a bortle 9 zone.
Places where I host my other images:
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TPO 6" F/4 Imaging Newtonian
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Orion Sirius EQ-G
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ZWO ASI1600MM-Pro
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Skywatcher Quattro Coma Corrector
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ZWO EFW 8x1.25"/31mm
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Astronomik LRGB+CLS Filters- 31mm
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Astrodon 31mm Ha 5nm, Oiii 3nm, Sii 5nm
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Agena 50mm Deluxe Straight-Through Guide Scope
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ZWO ASI-290mc for guiding
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Moonlite Autofocuser
Acquisition: 57 hours 40 minutes (Camera at -15°C), NB exposures at unity gain and BB at half unity
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Ha - 111x600"
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Oiii - 127x600"
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Sii - 94x600"
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R - 48x60"
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G - 48x60"
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B - 44x60"
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Darks- 30
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Flats- 30 per filter
Capture Software:
- Captured using N.I.N.A. and PHD2 for guiding and dithering.
PixInsight Preprocessing:
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BatchPreProcessing
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StarAlignment
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Blink
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ImageIntegration per channel
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DrizzleIntegration (2x, Var β=1.5)
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Dynamic Crop
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DynamicBackgroundExtraction
duplicated each image and removed stars via StarXterminator. Ran DBE with a shitload of points to generate background model. model subtracted from original pic using the following PixelMath (math courtesy of /u/jimmythechicken1)
$T * med(model) / model
Narrowband Linear:
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Blur and NoiseXTerminator
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StarXterminator to completely remove stars (to be later replaced by the RGB ones)
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HistogramTransformation to stretch nonlinear
RGB Linear:
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ChannelCombination to combine monochrome R G and B frame into color image
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SpectroPhotometricColorCalibration
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BlurXTerminator for star sharpening (correct only)
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HSV Repair
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StarXterminator to generate a stars-only image
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ArcsinhStretch + HT to stretch nonlinear (to be combined with starless narrowband image later)
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Invert > SCNR > invert to remove magentas
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Curves to saturate the stars a bit more
Nonlinear:
- PixelMath to combine monochrome Ha Oiii and Sii images into a color image with Jimmy's Royale Palette
R = 0.3*Oiii+0.7*(Oiii^~(0.7*Ha+0.3*Sii))^1.2
G = ((Oiii*Ha)^~(Oiii*Ha))*Ha + ~((Oiii*Ha)^~(Oiii*Ha))*Sii
B = 0.9*Sii+Ha-Oii
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NoiseX again
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Shitloads of Curve Transformations to adjust lightness, hues, contrast, saturation, etc
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more curves
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Extract L --> LRGBCombination for chrominance noise reduction
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even more curves
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Pixelmath to add in the stretched RGB stars only image from earlier
This basically re-linearizes the two images, adds them together, and then stretches them back to before. More info on it here)
mtf(.005,
mtf(.995,Stars)+
mtf(.995,Starless))
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Couple final curves
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Resample to 60%
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Annotation