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Contains:  Helix nebula, NGC 7293

Image of the day 09/06/2015

Getting plate-solving status, please wait...
    Helix Nebula, 





    
        

            rflinn68
    Helix Nebula

    Helix Nebula

    Technical card

    Resolution: 3410x2705

    Dates:Aug. 10, 2015Aug. 11, 2015Aug. 12, 2015Aug. 13, 2015

    Frames:
    Astrodon 5nm H-alpha: 24x900" bin 1x1
    Astrodon 5nm OIII: 19x900" bin 2x2
    Astrodon Blue Tru-Balance E-series: 12x300" bin 2x2
    Astrodon Green Tru-Balance E-series: 12x300" bin 2x2
    Astrodon Luminance Tru-Balance E-series: 18x600" -10C bin 1x1
    Astrodon Red Tru-Balance E-series: 12x300" bin 2x2

    Integration: 16.8 hours

    Darks: ~20

    Flats: ~30

    Bias: ~100

    Avg. Moon age: 27.06 days

    Avg. Moon phase: 7.87%

    Astrometry.net job: 760265

    RA center: 337.406 degrees

    DEC center: -20.805 degrees

    Orientation: 1.897 degrees

    Field radius: 0.957 degrees

    Locations: Little Piney Observatory, Hagarville, Arkansas, United States

    Description

    The Helix Nebula, also known as The Helix, NGC 7293, is a large planetary nebula (PN) located in the constellation Aquarius. Discovered by Karl Ludwig Harding, probably before 1824, this object is one of the closest to the Earth of all the bright planetary nebulae. The estimated distance is about 215 parsecs (700 light-years). It is similar in appearance to the Cat's Eye Nebula and the Ring Nebula, whose size, age, and physical characteristics are similar to the Dumbbell Nebula, varying only in its relative proximity and the appearance from the equatorial viewing angle. The Helix Nebula has sometimes been referred to as the "Eye of God" in pop culture, as well as the "Eye of Sauron". --Wiki

    I struggled with this one, wanting to show the numerous background galaxies in the area that are visible only with broadband filters, and using narrowband filters to try to see as much detail as possible in this structure. As an aside, I think that maybe broadband would be all that was needed here. But anyway, PixInsight's Pixel Math came to the rescue here.

    I think I tried about 100 different combinations on this one, but finally came up with something that was I felt was a good compromise between the details of narrowband and the broadband filters to show the galaxies. Dont ask me to try to remember exactly what it was as I've since deleted the files, but the Pixel Math expression something like this....

    R/K: 0.6*Ha + 0.4*Lum
    G: 0.4*OIII + 0.3*Ha + 0.3*Lum
    B: 0.7*OIII + 0.3*Lum

    After coming up with an image from this expression I then worked on blending in the RGB. It was a balancing act for sure, but I hope I've come close to showing a good representation of this area of the sky. Please check out the annotated version that has most of the galaxies labeled. There's one galaxy that can be seen through the Helix that was not labeled. Of course none of these galaxies showed up with the narrowband data, so it was a struggle to find a happy medium.

    Comments

    Author

    rflinn68
    rflinn68
    License: None (All rights reserved)
    11946
    Like

    Revisions

      Helix Nebula, 





    
        

            rflinn68
      Original
      Helix Nebula, 





    
        

            rflinn68
      B
      Helix Nebula, 





    
        

            rflinn68
      C
    • Final
      Helix Nebula, 





    
        

            rflinn68
      D

    Sky plot

    Sky plot

    Histogram

    Helix Nebula, 





    
        

            rflinn68