The Coalsack Nebula
|Observation data (Epoch J2000.0)|
|Right ascension||12h 50m|
|Distance (ly)||600 ly|
|Apparent magnitude (V)||–|
|Apparent dimensions (V)||7 × 5 °|
|Absolute magnitude (V)||–|
|This article's listed sources may not meet Wikipedia's guidelines for reliable sources. (October 2012)|
The Coalsack Dark Nebula (or simply the Coalsack) is the most prominent dark nebula in the skies, easily visible to the naked eye as a dark patch silhouetted against the southern Milky Way. It was known pre-historically in the Southern Hemisphere and was observed by Vicente Yáñez Pinzón in 1499. The Coalsack is located at a distance of approximately 600 light years away from Earth, in the constellation Crux.
 General information
The Coalsack Dark Nebula covers nearly 7° by 5° and overlaps somewhat into the neighbour constellations Centaurus and Musca. Although this nebula was known to the people of the Southern Hemisphere in prehistoric times, its first observation was reported by Vicente Yáñez Pinzón in 1499. It was named “il Canopo fosco” (the dark Canopus) by Amerigo Vespucci and was also called “Macula Magellani” (Magellan's Spot) or “Black Magellanic Cloud” in opposition to the Magellanic Clouds.
In 1970, Kalevi Mattila proved the Coalsack is not totally black; it has a very dim glow (10% of the brightness of the surrounding Milky Way) which comes from the reflection of the stars it obscures.
The Coalsack is important in Australian Aboriginal astronomy, and forms the head of the Emu in the sky in several Aboriginal cultures. Amongst the Wardaman people, it is said to be the head and shoulders of a law-man watching the people to ensure they do not break traditional law. According to a legend reported by W.E. Harney, this being is called Utdjungon and only adherence to the tribal law by surviving tribe members could prevent him from destroying the world with a fiery star.
 In fiction
- William F. Warren, Paradise found; the cradle of the human race at the North pole; a study of the prehistoric world, pp. 119-120.
- Songs of the Songmen, 28-30.
- p. 5, The Hundred Greatest Stars, James B. Kaler, New York, Copernicus Books, 2002.
- A.F. Aveni, ed. (2010). Archaeoastronomy in the New World : American primitive astronomy : proceedings of an international conference held at Oxford University, September, 1981. Cambridge: Cambridge University Press. ISBN 0521125472.
- Starry Night Photography: Coalsack Dark Nebula
- Starry Night Photography: The Emu
- SIMBAD: Coal Sack Nebula