|Right Ascension||12 : 52. (h:m)
|Declination||-63 : 18 (deg:m)
|Apparent Dimension||420x240 (arc min)
The Coalsack is the most prominent and conspicuous dark nebula in the skies, well visible to the naked eye as big dark patch in the Milky Way, This object is easily seen in the southern part of the Southern Cross and covers and obscures about 26 square degrees of the sky. It overlaps the borders of Crux so that parts of it are in the constellations Musca and Centaurus.
The image here was obtained by David Malin and is copyrighted; it may be freely used for private purpose only. For any other kind of use, including internet mirroring and storing on CD-ROM, please contact the Photo Permissions Department (photo at aaoepp.aao.gov.au) of the Anglo Australian Observatory.
Shown is the southern Milky Way in the constellations (left to right) Centaurus, Crux and Carina. The dark Coalsack is prominently visible. Also visible are several open clusters and diffuse emission nebulae, especially in Carina in the upper right.
In 1970, K. Mattila of Heidelberg has succeded to prove that the Coalsack is not totally black, but glowing in a very dim or feeble light, reflected from the stars it obscurs; Mattila found it to have 10 percent of the brightness of the surrounding Milky Way - but contrast makes it appear darker than every other part of the sky [according to Murdin, Allen and Malin (1979)].
The Coalsack dark nebula was pre-historically known to the people of the Southern Hemisphere. R.H. Allen (1899) reports that it was first observed by a European in 1499, namely by Portugese navigator Vincente Yanez Pinzon. Amerigo Vespucci named it "il Canopo fosco" in about 1503-4, and it was also called "Macula Magellani" (Magellan's Spot) or "Black Magellanic Cloud". The first formal description was given by Peter Martyr between 1511 and 1521. Later, Abbe Lacaille reported of this southern object from his 1751-52 voyage to South Africa, in an appendix to his 1755 catalog.
Last Modification: April 19, 2006