IC 5146 the Cocoon Nebula is a reflection nebula in the constellation Cygnus.
When viewing IC 5146, dark nebula Barnard 168 is an inseparable part of the experience, forming a dark lane that surrounds the cluster forming the appearance of a trail behind the Cocoon.

Technical info:
TS 80mm f6 APO triplet refractor - Canon 40D + IDAS LPS2 (light pollution) filter - exposure 48x 5min (4hours)