• lefty7283@lemmy.worldOPM
    link
    fedilink
    English
    arrow-up
    2
    ·
    5 days ago

    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