IC 5146: Cocoon and its Host Nebula (Alex Woronow)

IC 5146: Cocoon and its Host Nebula

IC 5146: Cocoon and its Host Nebula
OTA:                      CDK 17
Camera:               FLI Proline 16803
Observatory:      owned by Bernard Miller (New Mexico)EXPOSURES:
Red:       07 x 900 seconds
Blue:      11 x 900
Green: 06 x 900
Lum:      13 x 1200
Total exposure 10.3 hoursImage Width: 42 arcSec
Processed by Alex Woronow (2021) PixInsight, Topaz, 3DLut, SWT

The star cluster IC 5146 and its associated reddish cloud, the Cocoon Nebula (Sh2-125), lie within an extensive faint reflection/dark nebula. That pervading nebula imposes a haziness over the nebula, which conceals fine-scale detail and a pervasive ruddy tinge to the entire image. Many image processors appear to favor de-emphasizing the faint nebula and posing the Cocoon nebula on a blacker, blank sky, and removing much of the haze from in front of the nebula itself. The Cocoon molecular cloud is a highly active stellar nursery with hundreds of identified YSOs (Young Stellar Objects). According to (1), the bright ‘central’ star BD+46°3474 “…formed near the near surface of the present cloud and evacuated a blister cavity out of which gas and dust are now flowing through a funnel-shaped volume in the approximate direction of the Sun. It is suggested that the IC 5146 cluster stars formed in a dense foreground section of the molecular cloud that was dissipated following the appearance of +46°3474.”

(1)    Herbig & Dahm, The Young Cluster IC 5146, AJ, 2002

A version of “Lucky Imaging” was implemented here. Subs from all channels were rather severely graded, and a total capture time of about 16 hours of frames that passed scrutiny through blinking was pruned to the 10 hours used here. Even within those 10 hours used, subs were weighted to emphasize the deepness of capture, as measured by star abundance and ellipticity. This image has been down-sampled by a factor of about 2.5 from its full-frame parent.

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Status	Advanced success
Started	...
PixInsight job	N80Y27BPZ7BRXZ4AJD8T6XAFYNRUO2PU
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	21h53m44s.99
RA (top/left)	21h51m39s.92
RA (top/right)	21h55m43s.76
RA (bottom/right)	21h55m51s.53
RA (bottom/left)	21h51m44s.70

Dec (center)	+47°16′01″.8
Dec (top/left)	+46°55′40″.7
Dec (top/right)	+46°54′36″.4
Dec (bottom/right)	+47°36′16″.1
Dec (bottom/left)	+47°37′18″.4

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