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Astrophotography @lemmy.world lefty7283 @lemmy.world

DWB 111 - The Propeller Nebula

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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