IC 5146 (also Caldwell 19, Sh 2-125, and the Cocoon Nebula)
is a reflection /emission nebula and Caldwell object in
the constellation Cygnus. The NGC description refers to IC 5146
as a cluster of 9.5 mag stars involved in a bright and dark nebula.
The cluster is also known as Collinder 470. It shines at
magnitude +10.0 /+9.3[2]/+7.2. Its celestial coordinates are
RA 21h 53.5m, dec+47° 16′. It is located near the naked-eye star
Pi Cygni, the open cluster NGC 7209 in Lacerta, and the bright open
cluster M39.[1][4] 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 equivalent to a span of 15 light years.

When viewing IC 5146, dark nebula Barnard 168 (B168) is an inseparable
part of the experience, forming a dark lane that surrounds the cluster
and projects westward forming the appearance of a trail behind the Cocoon.