IC 5146, also known as the Cocoon Nebula, is a reflection and emission nebula located in the constellation Cygnus. It has a diameter of about 15 light years and is part of an extended molecular cloud. The original 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. The dark nebula Barnard 168 (B 168) forms a dark lane that surrounds the cluster and projects westward forming the appearance of a trail behind the Cocoon. Young stars have been found in both the emission nebula, where gas has been ionized by massive young stars, and in the infrared-dark molecular cloud that forms the "tail".

There are four open star clusters identifiable within this image:

• M39, the apparently largest of them, to the right;
• NGC 7209 to the left;
• NGC 7086 near the upper right corner;
• NGC 7093 just above ρ Cyg, the brightest star in this image, near the right edge.

Sh2-124 is a huge but faint emission nebula covering much of the upper right sector of this image. Only the brightest part of it can be seen as red patch near the center of its circle.

Milky Way Vista - Cygnus to Cassiopeia, zoom lens photograph.
M39, Wright-Newtonian photograph.
IC 5146 - Cocoon Nebula, Triplet telescope image.