• lefty7283@lemmy.worldOPMEnglish
    3·
    2 months ago

    I totally didn’t procrastinate processing this thing, and it’s just pure coincidence that I finally took a stab at it in October…

    In hindsight, this really could’ve used another night of data (particularly the L), but I only had one clear night at the dark site. I was just happy to get out of the light pollution and shoot a dark nebula for once! Captured on August 17th, 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: 7 hours 21 minutes (Camera at -15°C), half unity gain

    • L - 56x180"

    • R - 30x180"

    • G - 30x180"

    • B - 31x180"

    • 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)

    For the L channel I did 3 stacks each with 1/3rd of the data, then combined them to an RGB image (was still grayscale) to use deepSNR noise reduction. after this it was properly converted to mono

    • Dynamic Crop

    • MultiscaleGradientCorrection

      First time trying out the MARS thing in pixinsight. It seems to work very well

    Luminance Linear:

    • BlurXterminator

    • 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

    • MultiscaleGradient Correction

    • 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 and magentas

    • Curves to boost saturation

    Nonlinear Processing:

    • LRGBCombination to combine stretched RGB and L images

    • DeepSNR Noise reduction

    • Several rounds of curve adjustments for lightness, contrast, saturation, color balance, with various masks

    • LocalHistogramEqualization

    • 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))

    • BlurX to sharpen the stars a little

    • Even more curves

    • Slight SCNR

    • Resample to 70%

    • Tighter crop in on just the nebula

    • Annotation