IC5146 The Cocoon Nebula and Massive Star Field (Jim Raskett)

IC5146 The Cocoon Nebula and Massive Star Field

Revision title: Less Stars, More Dust

"IC 5146 (also Caldwell 19, Sh 2-125, Barnard 168, 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.[4] It shines at magnitude +10. 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, 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".

A very modest image of the Cocoon Nebula . The five hours of integration that I collected just isn’t enough time in my B7 skies. This endeavor began as a guiding test.

I had some bumpy DEC performance recently and tweaked the DEC worm carrier on my HEQ5. I set up mainly to calibrate PHD2 and run the Guiding Assistant to check the DEC backlash.It was still very early, so I decided to image something to test guiding dither recovery.

I looked around in Skyafari and saw the Cocoon Nebula in good position to get several hours of imaging in. I still had the uv/ir cut filter in the drawer and was too lazy to get out the L-eNhance, so I went left things as is.

I have never imaged the Cocoon but hoped that if things looked good, I could get more time on it soon. Well, that might not happen, so I decided to pass the data through Pixinsight’s WBPP and see what I had.

This is a wide field shot, so “My God, It’s full of stars” definitely applies! It’s the most dense star field that I’ve seen, but the star field is pretty cool. I tried several versions of star reduction, but I actually like the full star field image better. The dust trail of the Cocoon is quite prevalent, however, the stars really cover it up.

The stars were removed during processing the nebula and re-added without any modifications to saturation (or anything).

Hope to add more data next year with the L-eNhance filter.

Thanks for looking!

Jim

Original
Final
B

B

Title: Less Stars, More Dust

Description: Been working on dust enhancing techniques recently. In the original process, I really couldn't get much out of the background, so I just let the stars roll in all of their glory.
Unfortunately, this image is only just a tad over 5 hours of integration. Not nearly enough in my Bortle 6-7 skies to bring out dust, but I will be limited in my ability to collect more data for a month or two. Looking at next year on this target before I will have the opportunity to collect more data, so here goes!
Thanks for looking!

Jim

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Status	Advanced success
Started	...
Astrometry.net job	7275235
PixInsight job	K4Y2MMR07GE19YOEGB61CS620QOLX7Y5
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	21h53m22s.60
RA (top/left)	21h46m00s.54
RA (top/right)	21h46m48s.24
RA (bottom/right)	22h00m24s.55
RA (bottom/left)	22h00m14s.44

Dec (center)	+47°16′22″.6
Dec (top/left)	+48°23′52″.2
Dec (top/right)	+46°02′21″.7
Dec (bottom/right)	+46°06′59″.9
Dec (bottom/left)	+48°28′53″.2

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