• lefty7283@lemmy.worldOPEnglish
    3·
    1 year ago

    VdB 152 is technically just one part at the end of the dark nebula, and there are a number of other cataloged structures in this image. Captured from August 16-25, 2023. Broadband data from a Bortle 3 zone (Deerlick astronomy village), Ha from Bortle 9.

    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: 30 hours 15 minutes (Camera at -15°C)

    BB exposures at half unity gain (76/15), Ha at unity gain (139/21)

    • Ha - 102x600"

    • L - 200x120"

    • R - 70x120"

    • G - 70x120"

    • B - 68x120"

    • 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 per panel

    • DrizzleIntegration (2x, Var β=1.5)

    • Dynamic Crop

    • DynamicBackgroundExtraction

    Luminance Linear:

    • BlurXterminator

    • NoiseXterminator

    • ArcsinhStretch + HistogramTransformation to stretch to nonlinear

    Ha Linear:

    These steps largely follow the ones in NightPhoton’s advanced narrowband combination guide.

    • Combine Ha with Red channel (HRR palette)

    • BackgroundNeutralization

    • ColorCalibration

    • StarXterminator to completely remove stars

    • PixelMath to subtract red continuum spectrum, leaving just Ha signal

    • HistogramTransformation to stretch nonlinear

    • NoiseXterminator + a little concolution

    • CurvesTransformation to adjust black point/contrast

    differing from the guide above, the background was a dark gray rather than clipped to black since this is more faint structure addition than bright structure

    RGB Linear:

    • SpectrophotometricColorCalibration

    • Slight SCNR Green

    • HSV repair

    • ArcsinhStretch + HistogramTransformation to stretch to nonlinear

    duplicate stars only was made and stretched to nonlinear using a less aggressive arcsin+HT for star addition later

    Nonlinear Processing:

    • Various curve adjustments for lightness, contrast, hue, saturation, etc (with varying lum/star masks)

    • LRGBCombination using stretched L as luminance

    • DeepSNR

    • More curves

    • PixelMath to add stretched Ha per the advanced narrowband guide above

    • BlurXterminator for star reduction

    Next few steps kinda follow along with this independent starless processing tutorial for manually combining stars via re-linearization

    • StarXterminator

    • HistogramTransformation to unstretch (also applied to duplicate stars early image from earlier)

    • PixelMath to combine starless + stars only images

    • HT to stretch everything back to nonlinear

    • Guess what more curves

    • MultiscaleLinearTransform for chrominance noise reduction

    • LocalHistogramEqualization (2 rounds of this at scales 68 and 384 with lum masks)

    • ColorSaturation to selectively saturate reds

    • Even more curves

    • Resample to 70%

    • Annotation