IC 5146: Cocoon Nebula

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IC 5146 (also Caldwell 19Sh 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/+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.

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.

Imaging telescopes or lenses: Meade Model 2080
Imaging cameras: Canon 600D
Mounts: Sky-Watcher HEQ5 PRO
Guiding telescopes or lenses: Celestron 80mm Guidescope
Guiding cameras: Sky-Watcher Synguider
Focal reducers: Meade f/6.3
Software: PixInsight, BinaryRivers BackyardEOS
Dates: Nov. 5, 2013
Locations: Roof terrace, Borås, Sweden
Frames: 15×240″ ISO1600
Integration: 1.0 hours
Darks: ~9
Flats: ~10
Bias: ~20

Author: Peter Folkesson

AstroPhotography of the day by SPONLI
21 May 2014