IC 5146, also Caldwell 19 and the Cocoon Nebula, is a reflection/emission nebula and Caldwell object in the constellation Cygnus. The cluster is about 4,000 ly away, and the central star that lights it formed about 100,000 years ago; the nebula is about 12 arcmins across, which is equavalent to a span of 15 light years. When viewing IC 5146, dark nebula Barnard 168 (B168) is an inseperable part of the experience, forming a dark lane that surrounds the cluster and projects westward forming the appearance of a trail behind the Cocoon. [Wikipedia]