Sh2-125, IC5146 "Cocoon Nebula"

CLICK ON IMAGE FOR FULL SIZE VIEW (6006x4090)

Scope: Celestron 9.25 Edge HD 235 mm at f/7; Location: DAA Observatory, Shelter Valley, CA;  Dates:  10, 12, 16 August 2023; Camera: ASI294MM (Baader  Ha, L, RGB Filters)

Exposure: Ha 64 x 3.5 minutes (gain-140 2x2) ,  Lum 128 x 3. minutes (gain-121 2x2), RGB - 40 each x 2 minutes  - (gain-121 2x2).

Processing: Data Collection -  N.I.N.A. (as FITs).  Sub-frame calibration - Pixinsight (WBPP). Sub-frame  registration and integration (Average combine -  Winsorized sigma clipping,  2X drizzle for Ha, Lum) - PixInsight (WBPP).  NoiseXTerminator (RGB, Ha, Lum) - PixInsight.  Non-linear stretching for Ha and Lum - PixInsight.    RGB combine and stretching, Photometric RGB calibration (SPCC)  - PixInsight. Generation of starless Ha, Lum, and RGB image for later processing - StarXTerminator  (PixInsight.)  De-convolution - BlurXTerminator (AI4) - PixInsight.  Lum  stack with core Ha luminance layering - PixInsight.  RGB star image is screened into the Lum / Ha starless construction - Pixinsight. Final finishing  - Affinity Photo.  Annotation - PixInsight, Aladin (Simbad), and Affinity Photo. This image is a starless L(Ha)RGB with RGB stars.  Image processed at 8288x5644 resolution (2x drizzle stacks). Final Image size is approximately 6006x4090.

North is up in this image.  It is a close up image of IC 5146 / Sh2-125 / LBN 424 "Cocoon Nebula". IC 5146  (Collinder 470) is designated as an open cluster. Sh2-125 is designated as an HII region. These catalog designations generally refer to the same  structure as a "cluster with emission nebula". Distance of Sh2-125 is from 3,000 to 3,300 light years. The emission structure is ionized by star BD +46 - a high proper motion star.  

Also in the image is the reflection Nebula  vdB 147 just to the right of the Cocoon. There are three little galaxies in the lower left (LEDA 167590, 167593, and 167597) - the furthest is LEDA 167590 at about 1,129 million light years (by redshift estimate). Much of the dust and interstellar matter in this field is designated as the Dark Nebula LDN 1055.   These objects, information, and some of the brighter stars are identified in the annotated image.  This image replaces an earlier image that can be seen in the Archives Here. The Horizontal FOV is approximately 0.672 degrees. Full size image scale is approximately 0.403 arcsec/pix.

Image Center approximately - Equatorial 2000: RA: 21h 53m 26s Dec: +47°16'05"

All images and content remain the property of Jim Thommes - copyright 2003 - 2024

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