• lefty7283OPMEnglish
    2·
    2 days ago

    So I originally shot this back in 2020 from my in-law’s house in a Bortle 4 area. Only got a handful of LRGB subs because my guide cam did not wanna talk to my laptop for most of the session back then. Recently I decided to shoot some Ha from my B9 apartment and give it a reprocess in HaLRGB. Overall I’m very pleased with this improvement after 6 years! Captured captured in February 2020 and December 2025 from bortle 4 and 9, respectively.

    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: 9 hours 55 minutes (Camera at unity gain, -15°C)

    • Ha - 48x600"

    • L - 12x300"

    • R - 4x300"

    • G - 4x300"

    • B - 3x300"

    • 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:

    • BlurXterminator

    • StarXterminator to completely remove stars (extracted stars processed separately)

    • STF applied via HistogramTransformation to stretch nonlinear

    Ha Processing:

    • StarX to remove stars

    • Subtracted red continuum to create a ‘clean’ Ha image using pixelmath

    • Pixelmath to combine the clean Ha image into the RGB image

    largely following this advanced narrowband combination guide, also made by jimmy

    RGB Linear:

    • Channelcombination to make color image from RGB stacks

    • SpectrophotometricColorCalibration

    • StarX to remove stars (to be used for star addition later)

    • PixelMath per the advanced narrowband guide to add Ha into the red and blue channels

    • ArcsinhStretch + HistogramTransformation to stretch nonlinear

    • Slight curves saturation boost and histogram adjustments

    Stars only image:

    • BlurXterminator for discortion correction and some mild star reduction

    • HSV repair

    • ArcsinhStretch + HistogramTransformation to stretch nonlinear (less aggressive stretch)

    • Slight curve adjustments

    Nonlinear Processing

    • LRGBCombination to combine stretched RGB and L images

    • DeepSNR Noise reduction

    • Shitloads of curve transformations to adjust luminance, contrast, saturation, etc

    • More curves

    • LocalHistogramTransformation

    • 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. More info on it here

      mtf(.005,

      mtf(.995,Stars)+

      mtf(.995,Starless))

    • NoiseXTerminator for some small scale chrominance noise reduction

    • Resample to 70%

    • DynamicCrop in on just the galaxy (not a whole lot going on in the background)

    • Annotation