Imaged the Cocoon Nebula (IC 5146) over the course of six nights in November 2023.
Per WIkipedia (
https://en.wikipedia.org/wiki/IC_5146): "
IC 5146 (also
Caldwell 19,
Sh 2-125,
Barnard 168, and the
Cocoon Nebula) is a
reflection=reference
[2]/
emission=reference
[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.=reference
[4] It shines at magnitude +10.0=reference
[5]/+9.3=reference
[3]/+7.2.=reference
[6] Its celestial coordinates are RA =nowrap21h 53.5m , dec +47° 16′. It is located near the [url=mw-redirect=https://en.wikipedia.org/wiki/Naked-eye]naked-eye[/url] star
Pi Cygni, the open cluster
NGC 7209 in
Lacerta, and the bright open cluster
M39.=reference
[2]=reference
[5] The cluster is about 4,000 ly away, and the central star that lights it formed about 100,000 years ago;=reference
[7] the nebula is about 12 arcmins across, which is equivalent to a span of 15 light years.=reference
[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."
Imaged with a William Optics GT81 at F4.7 (382 mm focal length) using Flat6A II field flattener/0.8x reducer, Optolong LeNhance dual narrowband and UVIR cut filters, and ZWO ASI 533MC Pro.
Total integration time of ~13 hours:
LENH NB filter = 138 subs at Gain = 100 with an exposure time of 300 seconds
UVIR cut filter = 67 subs at Gain = 100 with an exposure time of 120 seconds
Processing:
- All images pre-processed using Pixinsight's weighted batch pre-processing script (WBPP) to perform calibration, debayering, registration, local normalization, and integration. Background removed using GradXpert. Initial post-processing in Pixinsight: spectrophotometric color calibration, blur x terminator, and noise x terminator.
- RGB stars image processing (UVIR cut filter data): Color saturation boost and GHS2 stretch. Generated stars only version using StarXterminator.
- Starless image processing (narrowband data): Generated starless version using StarXterminator. GHS2 generalized hyperbolic stretch, curves adjustment (using GAME generated mask to protect the nebula), and ezHDR script. Narrowband normalization process (Mode 1) used to generate SHO palette style image.
- Final image generated by combining stars only and starless images using Pixelmath process.
Original version: IC 5146 in HOO
Rev B: IC 5146 in HOO, starless
Rev C: IC 5146 in HOO, H-alpha data
Rev D: IC 5146 SHO style
Rev E: IC 5146, RGB data only
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