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Contains:  M 31, Great Nebula in Andromeda, NGC 224, M 32, NGC 221, M 110, NGC 205

Image of the day 01/18/2019

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    The Andromeda Galaxy - M31, 





    
        

            Andrew Klinger
    The Andromeda Galaxy - M31

    The Andromeda Galaxy - M31

    Technical card

    Resolution: 2619x3558

    Dates:Nov. 2, 2018Dec. 1, 2018Dec. 15, 2018

    Frames:
    ZWO B 1.25": 40x300" (gain: 76.00) -20C bin 1x1
    ZWO G 1.25": 44x300" (gain: 76.00) -20C bin 1x1
    Astrodon Ha 5nm: 115x300" (gain: 200.00) -20C bin 1x1
    ZWO L 1.25": 143x300" (gain: 76.00) -20C bin 1x1
    ZWO R 1.25": 46x300" (gain: 76.00) -20C bin 1x1

    Integration: 32.3 hours

    Darks: ~64

    Flats: ~30

    Bias: ~200

    Avg. Moon age: 18.40 days

    Avg. Moon phase: 37.95%

    Bortle Dark-Sky Scale: 3.80

    Astrometry.net job: 2457922

    RA center: 10.683 degrees

    DEC center: 41.262 degrees

    Pixel scale: 2.527 arcsec/pixel

    Orientation: 181.083 degrees

    Field radius: 1.551 degrees

    Locations: Atoka dark site, Atoka, Oklahoma, United States; Backyard, Flower Mound, Texas, United States

    Data source: Traveller

    Description

    I present to you my Fall project, the Andromeda Galaxy. The last time I imaged M31 was two years ago with my DSLR, but all other equipment being generally the same. I'm glad to finally give M31 a proper go with the astronomy camera, as it just explodes with color and little red nebulous regions within.

    Equipment:
    OTA: William Optics GT81 w/0.8x reducer/flattener (382mm fl at f/4.7)
    Mount: Orion Sirius EQ-G (HEQ-5)
    Guidescope: Orion 50mm guidescope
    Guiding camera: Orion StarShoot Autoguider
    Imaging camera: ZWO ASI1600MM-Cool

    Accessories:
    QHYCCD PoleMaster

    Software:
    SGP
    PHD2
    CdC
    PixInsight

    Acquisition:
    Location: Atoka, OK and Ft. Griffin State Historic Park, TX for LRGB(Bortle 3), Flower Mound, TX for Ha(Bortle 7)
    Dates: 11/2/18, 11/5/18, 12/1/18, 12/9/18, 12/15/18, 12/22/18, 12/23/18
    Gain: 76 Offset: 15 for LRGB
    Gain: 200 Offset: 50 for Ha
    Camera temp: -20C
    L: 143x300" ZWO
    R: 46x300" ZWO
    G: 44x300" ZWO
    B: 40x300" ZWO
    Ha: 115x300" Astrodon 5nm
    Total integration time: 32hr 20min
    64x darks per calibration (master from library)
    30x flats per calibration
    200x bias per calibration (master from library)

    Preprocessing:
    Batch PreProcessing script to generate calibrated images
    StarAlignment
    LocalNormalization
    ImageIntegration
    DrizzleIntegration
    DynamicCrop each master
    DBE each master

    Luminance Processing:
    Deconvolution
    TGV & MMT noise reduction (via Jon Rista's method)
    HistogramTransformation x2 (Linear > Non-Linear)
    HDRMultiscaleTransform
    LocalHistogramEqualization
    MLT sharpening
    MMT for slight star reduction

    Preparing separate R,G,B masters for combination (applied to each master individually):
    TGV & MMT noise reduction (via Jon Rista's method)
    LinearFit to B master

    Preparing Ha master for combination:
    TGV & MMT noise reduction (via Jon Rista's method)
    Removed stars with several iterations of MMT and MT
    MMT to remove any artifacts left in the background
    DBE to even out the background

    Combined processed Red and Ha master with PixelMath:
    Red*0.9 + Ha*0.1

    Created HaRGB image with ChannelCombination

    HaRGB Processing:
    BackgroundNeutralization
    ColorCalibration
    SCNR Green
    ArcsinhStretch x2
    HistogramTransformation (Linear > Non-Linear)
    HDRMultiscaleTransform
    CurvesTransformation for saturation
    ColorSaturation tool to specifically saturate the Ha regions

    Combined HaRGB with Luminance using LRGBCombination

    LHaRGB Processing:
    MT for slight star reduction
    UnsharpMask to harden up the soft stars slightly
    SCNR Green
    CurvesTransformation for final saturation tweak
    Resampled to 40% for web posting

    Comments

    Author

    ak_astro
    Andrew Klinger
    License: None (All rights reserved)
    147121
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    The Andromeda Galaxy - M31, 





    
        

            Andrew Klinger