From Wiki:
IC 5146 (also
Caldwell 19,
Sh 2-125,
Barnard 168, and the
Cocoon Nebula) is a
reflection[2]/
emission[3]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.
[4] It shines at magnitude +10.0
[5]/+9.3
[3]/+7.2.
[6] 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.
[2][5] The cluster is about 4,000 ly away, and the central star that lights it formed about 100,000 years ago;
[7] the nebula is about 12 arcmins across, which is equivalent to a span of 15 light years.
[6]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.
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