The Coalsack Nebula (Southern Coalsack, or simply theCoalsack)[1] is a dark nebula, which is visible to the naked eye as a dark patch obscuring part of the Milky Way east of Acrux (Alpha Crucis) in the constellation of Crux.[2]
The Coalsack Nebula covers nearly 7° by 5° and extends into the neighboring constellations Centaurus and Musca.[4] The first observation was reported by Vicente Yáñez Pinzón in 1499.[5] 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.[5]
Файл:Emu public.jpgA depiction of the emu in the sky, which is an Australian Aboriginal constellation consisting of dark clouds rather than of stars. The European constellation on the right is Crux, or the Southern Cross, and on the left is Scorpius. The head of the emu is the Coalsack.
In Australian Aboriginal astronomy, the Coalsack 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.[6] There is also a reference by Gaiarbau (1880) regarding the coalsacks replicating bora rings on Earth. These astronomical sites allowed the spirits to continue ceremony similar to their human counterparts on Earth. As bora grounds are generally located on the compass points north–south, the southern coal sack indicates the ceremonial ring.
In Inca astronomy this nebula was called Yutu, after a partridge-like South American bird,[7] or Tinamou.[8]
