Probably should’ve gotten more exposure time on this, but it was already way out of season. Captured over several nights in January 2024, from a Bortle 9 zone

Places where I host my other images:

Flickr | Instagram

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Equipment:

• TPO 6" F/4 Imaging Newtonian

• Orion Sirius EQ-G

• ZWO ASI1600MM-Pro

• Skywatcher Quattro Coma Corrector

• ZWO EFW 8x1.25"/31mm

• Astronomik LRGB+CLS Filters- 31mm

• Astrodon 31mm Ha 5nm, Oiii 3nm, Sii 5nm

• Agena 50mm Deluxe Straight-Through Guide Scope

• ZWO ASI-290mc for guiding

• Moonlite Autofocuser

Acquisition: 10 hours 10 minutes (Camera at -15°C), Camera at unity gain.

• Ha - 35x360"

• Oiii - 31x360"

• Sii - 35x360"

• L - 200x120"

• Darks- 30

• Flats- 30 per filter

Capture Software:

• Captured using N.I.N.A. and PHD2 for guiding and dithering.

PixInsight Preprocessing:

• BatchPreProcessing

• StarAlignment

• Blink

• ImageIntegration per channel

• DrizzleIntegration (2x, Var β=1.5)

• Dynamic Crop

• 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:

• Blur and NoiseXTerminator

• Duplicated the images before stretching to be used for separate stars-only processing

• STF applied via histogramtransformation to stretch nonlinear

Stars Only Processing:

• StarXTerminator to make stars only image form each channel

• PixelMath to combine star images (SHO palette)

• SpectroPhotometricColorCalibration (narrowband working mode)

• SCNR Green

• ArcsinhStretch + HT to stretch nonlinear - to be combined later with starless pic

Nonlinear:

• PixelMath to combine stretched Ha, Oiii, and Sii images into color image (SHO palette)

• Invert > SCNR > invert > SCNR to remove greens and magentas

• Shitloads of Curve Transformations to adjust lightness, hues, contrast, saturation, etc

• LRGBCombination with stretched Ha as luminance

• more curves

• NoiseXterminator

• LocalHistrogramEqualization (at small and large scales to target varying structures)

• MLT for large scale chrominance noise reduction

• Extract L --> LRGBCombination for smaller scale chrominance noise reduction

• Pixelmath to add in the stretched stars only image from earlier

This basically re-linearizes the two images, adds them together, and then stretches them back to before

(Jimmy is a processing wizard when it comes to writing up this independent starless processing stuff)

mtf(.005,

mtf(.995,Stars)+

mtf(.995,Starless))

• more curves

• Resample to 60%

• Annotation