This object was discovered by E.E. Barnard in 1913. The dark nebula appears like a dark comet and obscures parts of M24 (the Small Sagittarius Star Cloud). It was one of the first dark nebulae to be discovered.
Barnard 145 is the horizontal dark area slightly below center in the image below.
is seen extending from it across above.
The Cocoon is primarily a red emission nebula (Sharpless-125. Embedded in the nebula is open cluster IC 5146.