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  • 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

    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