Page "Crux" Paragraph 13

The Coalsack Nebula is the most prominent dark nebula in the skies, easily visible to the naked eye as a prominent dark patch in the southern Milky Way.

It is large, five degrees by seven degrees, and is 600 light-years from Earth.

Not all of the nebula is in the borders of Crux ; some of it is technically in Musca and Centaurus.