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Sh2-157 "Lobster Claw" Region



Scope: FSQ-106N at f/5, Location: DAA Observatory, Shelter Valley, CA,  21, 27, 29 August 2022,  Camera: ASI2600MM (Astronomik type 2c RGB, 6 nm Ha, OIII filters)

Exposure: Exposure: Ha - 64 x 4.5 min (gain-160 1x1), OIII - 63 x 4.5 min (gain-160 1x1) ,  RGB -20 x 2 min (gain-100 1x1) each RGB exposures.

Processing: Data Collection -  Sequence Generator Pro (as FITs).  Sub-frame calibration - Pixinsight (WBPP). Sub-frame  registration and integration (Average combine -  Winsorized Sigma Clipping) - PixInsight (WBPP).  Mure Denoise - PixInsight. Non-linear stretching, normalization and gradient removal - PixInsight.  Generation of starless nebulosity Ha and OIII images for later processing - Star XTerminator. Curves, Levels, stars RGB combine, stars Luminance layering - PixInsight. Color Stars and Narrow band Starless  combine - PixInsight.  Final finishing  - Affinity Photo.  Photometric RGB calibration - PixInsight. Annotation - PixInsight, Aladin (Simbad), and Affinity Photo. This image is a  Bicolor narrow band image (modified HOO mapping) with RGB stars.  Image processed at 6248x4176 resolution. Final Image size is approximately  480x3186.

North is to the right in this image.  This image shows the emission nebula Sh2-175 (also known as LBN 536 and commonly called the "Lobster Claw") .  Included in the image is NGC 7635 (also known as Sh2-162, LBN 548, and commonly called the "Bubble Nebula"). Other objects are the compact HII region Sh2-157B / LBN 537; LBN 533, 540, 544, and 549; Sh2-159; NGC 7510 (open cluster); NGC 7538 (IR Cluster ad HII region). Also included are dark nebulae LDN 1225 and 1231.  The northern portion of Sh2-157 ("Claw") is ionized Wolf-Rayet star - WR 157; the southern portion (base of "Claw") may be ionized by multiple stars in that region. The distance of  the overall Sh2-157 structure is estimated to be about  8,100 to 13,700 light years distant. These objects and some of the brighter stars are identified in the annotated imageHorizontal FOV is approximately 152 arc minutes. Full size image scale is about 1.9 arcsec/pix.

Image center is approximately - Equatorial 2000: RA: 23h 16m 16s Dec: +60 35' 29"


All images and content remain the property of Jim Thommes - copyright 2003 - 2022

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