Another faint nebula from light polluted skies! Really like how the faint background dust in the Sii channel turned out in this. Captured over a bunch of nights from January-March 2025, 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: 68 hours 4 minutes (Camera at -15°C), unity gain
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Ha - 179x600"
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Sii - 219x600"
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R - 36x60"
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G - 35x60"
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B - 33x60"
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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 from each the image
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HistogramTransformation to stretch Ha and Sii images to nonlinear
Broadband/RGB linear:
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ChannelCombination to make color image from R G and B stacks
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SpectrophotometricColorCalibration
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HSV repair to fix blown out star cores
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StarX (correct only)
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StarX to make a stars only image
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ArcsinhStretch + Histogramtransformation to stretch nonlinear (Calling this the Stars image now)
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SCNR > Invert > SCNR (50%) > Invert to remove greens and some magentas from stars
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Slight saturation boost
Nonlinear:
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Pixelmath to combine stretched narrowband images into color image (HSS --> RGB)
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Shitloads of curve transformations to adjust lightness, contrast, saturation, color balance, etc
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ColorSaturation
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NoiseXterminator
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Pixelmath to add in the stretched RGB Stars 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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few more curve adjustments
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DynamicCrop again (just a little bit)
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Resample to 60%
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Annotation