• lefty7283@lemmy.worldOPMEnglish
    4·
    1 month ago

    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