Episode 239 – Observing Dark Nebula: A Beginner’s Guide Show Notes

Welcome to Episode 239 of the Actual Astronomy Podcast: Summer Shorts & Favourite Fields – Observing Dark Nebula: A Beginner’s Guide.

  • William Herschel was the first to notice these things when he was doing his sweeps in the 1780’s… he wrote of Scorpius “Here truly is a hole in the sky”
  • However, these were not holes and in the early 20th c. Barnard discovered they were masses of dust made visible because they were contrasted against background objects.
  • Dark Nebula Definition by Sky at Night:
    • A dark nebula is an interstellar cloud of cosmic dust that’s so dense it absorbs, scatters and blocks visible light, making it appear inky black when viewed against the starry cosmos. Famous examples of a dark nebula include the Coalsack Nebula, the Horsehead Nebula and the Snake Nebula.
  • Unlike the Stellar Magnitude system Dark Nebula are rated on darkness using an opacity scale, 1 being barely opaque while 6 is coal black.
  • Earth and Sky.org have a great depiction of the easiest one to see
  • The Great Rift is best viewed from a dark site with the eye and binoculars
  • This dark band is caused by interstellar clouds of cosmic dust that obscures the bright Milky Way, our home galaxy from your perspective on Earth. Basically what is happening is that you, the observer, are looking out at the bright Milky-Way star clouds but there are dark clouds of dust in between you and those star clouds.
  • Once you get this trick down of seeing the Dark Rift as a band look for
  • LG 3, Northern Coalsack, Barnard’s E and the Pipe Nebula

LG 3

Northern Coalsack

Barnards E


Pipe & Bowl Nebula

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