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3 comments

  • Beautiful image and beautiful work ... I'm an amateur astrophotographer that just likes to take a small digital camera to try to capture a few sky views and the Milky way with some landscape. The amount of work, time and effort I put into just a generic image takes a few hours of time, prep and then post processing.

    It's nothing compared to what you guys do and the weeks, months and years of work, training, experience and equipment you acquire and learn to use to generate images such as this. I fully appreciate everything that goes into a picture like this.

    Beautiful work ... I didn't know this community was here .. now I'm subscribed.

    Wow

  • Another image from my end of the year processing spree! I'm not entirely sure where the lion is in here, but it sure looks neat. I last shot this back in 2021, and overall I think this new go at it is a lot better color and noise wise. The region in the top left of the frame is incredibly rich in Oiii gas, which gives it a very distinct color difference from the rest of the nebula (no dynamic narrowband combination needed!). Captured over a shitload of nights from Sep-Nov, 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: 65 hours 45 minutes (Camera at -15°C), unity gain

    • Ha - 111x600"
    • Oiii - 141x600"
    • Sii - 130x600"
    • R - 42x60"
    • G - 42x60"
    • B - 41x60"
    • 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
    • StarXterminator to completely remove stars from each Ha, Oiii, and Sii image
    • HistogramTransformation to stretch nonlinear

    Broadband/RGB stars linear:

    • ChannelCombination to make color image from R G and B stacks
    • StarX (correct only)
    • SpectrophotometricColorCalibration (narrowband working mode)
    • HSV repair
    • StarXterminator to extract a stars-only image (to be used going forward)
    • arcsinhstretch
    • scnr > invert > scnr > invert to remove greens and magentas
    • HistogramTransformation
    • (combined with starless pic later on)

    Nonlinear:

    • PixelMath to combine monochrome Ha Oiii and Sii images into a color image with SHO --> RGB, respectively
    • HistogramTransformation to adjust red green and blue color channels separately (basically stretched R and B, and toned the G down some)
    • Slight SCNR green
    • NoiseXterminator
    • LRGBCombination using stretched extracted L channel as luminance
    • Shitloads of Curve Transformations to adjust lightness, hues, contrast, saturation, etc
    • LocalHistogramEqualization (two rounds of this. one at kernel radius 16 for small scale detail, and one at 500 for large structures)
    • More curves
    • 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))

    • guess what more curves
    • DynamicCrop again (I fucked up the framing a lil and had a lot of empty space towards the bottom)
    • Resample to 75%
    • Annotation