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 on the Southern Hemisphere and was observed by Vincente Yanez Pinzon in 1499. The Coalsack is located at a distance of approximately 600 light years away from Earth, in the Crux constellation.
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 Vincente Yanez Pinzon in 1499.
It was named “il Canopo fosco” by Amerigo Vespucci and was also called “Macula Magellani” (Magellan's Spot) or “Black Magellanic Cloud” in opposition to the Magellanic Clouds.
In 1970, K. 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 not present in the New General Catalogue and does not have an identification number.