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  • Another pic from my recent dark site trip! Decided to shoot something bright and in true color LRGB. If I had stayed another night and gotten more data I probably would've pushed the image more to get more background details, but overall I like this darker look on the image. Last time I shot this nebula was in 2022 using the false color OSH palette). Captured on July 26th, 2025 from a bortle 3 zone (deerlick astronomy village).

    Places where I host my other images:

    Flickr | Pixelfed

    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: 4 hours 2 minutes (Camera at -15°C), half unity gain

    • L - 49x120"
    • R - 267x120"
    • G - 23x120"
    • B - 23x120"
    • 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

    Luminance Linear:

    • Blur and noisexterminator
    • Stars removed with starx
    • ArcsinhStretch + HistogramTransformation to stretch nonlinear

    RGB Linear:

    • ChannelCombination to combine monochrome R G and B images in to single color image
    • SpectrophotometricColorCalibration
    • BlurXterminator (correct stars only)
    • HSV Repair
    • Extracted stars with starXterminator, to be used later for independent starless processing
    • ArcsinhStretch + HistogramTransformation to stretch nonlinear
    • Slight saturation curve boost

    ** Stars only processing:**

    • ArcsinhStretch + HistogramTransformation to stretch nonlinear
    • Slight SCNR to remove greens
    • Curves to boost saturation

    Nonlinear Processing:

    • LRGBCombination to combine stretched RGB and L images
    • NoiseX again (more for chrominance noise)
    • Several rounds of curve adjustments for lightness, contrast, saturation, color balance, with various masks
    • LocalHistogramEqualization (one at 16 scale for fine details, and another round at ~300 scale for larger structures)
    • More curves
    • Color Saturation
    • Even more curves
    • Slight SCNR on the background
    • 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))

    • Resample to 80%
    • Tighter crop in on just the nebula
    • Annotation