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Sh2-86, NGC 6820, 6823, Kronberger 9 (PN)



Scope: FSQ-106N at f/5, Location: DAA Observatory, Shelter Valley, CA; 12 and 20 May and 13 June, 2023,  Camera: ASI2600MM (Astronomik type 2c RGB, 6 nm Ha, OIII filters)

Exposure: Exposure: Ha - 67 x 3.5 min (gain-160 1x1), OIII - 61 x 3.5 min (gain-180 1x1) ,  RGB -24 x 2 min (gain-101 1x1) each RGB exposures.

Processing: Data Collection -  N.I.N.A. Sequencer (as FITs).  Sub-frame calibration - Pixinsight (WBPP). Sub-frame  registration and integration (Average combine -  ESD rejection) - PixInsight (WBPP).  Mure Denoise - PixInsight. Non-linear stretching, normalization and gradient removal - PixInsight. Photometric RGB calibration (SPCC) - PixInsight. Deconvolution of Ha OIII and RGB- BlurXTerminator. Generation of starless nebulosity Ha, OIII, and RGB images for later processing - Star XTerminator.  Curves, Levels, RGB combine, Range Compression - PixInsight.  RGB Stars and Narrow Band / Wide Band Starless  combine - PixInsight.   Final finishing  - Affinity Photo.   Annotation - PixInsight, Aladin (Simbad and NED), and Affinity Photo. This image is a  Bicolor Narrow Band starless image (modified HOO) and starless Wide Band image  combined to  make the starless composition - with RGB stars then added.  Image processed at 6248x4176 resolution. Final Image size is approximately  4029x6137.

The above image is a landscape crop of the full size portrait image (north up).  This image shows the region centered about Sh2-86 (also known as LBN 135) and the associated open cluster NGC 6823.  This open cluster is about 7,313 light years distant (by parallax). Just to the southeast (lower left) is a small but colorful planetary nebula (Kronberger 9). To the southwest is NGC 6820 (galactic nebula) which in the past has been identified with the larger emission structure  to the southwest, but more recently designated  (by the NGC/IC project and others) to be the smaller bright flare nebula at the same central coordinates.  Coincident with these coordinates is the very small open cluster Collinder 404. Other notable emission structures (one above and another to the right of Sh2-86) appear in a lesser known catalog as Du 28 and Du 26 (HII regions of the Northern Milky Way - R. Dubout-Crillon 1976).  There are several Dark Nebula from the TGU Catalog (optical, by star count method) and the Dobashi catalog (IR Band - 2MASS sky survey).   These objects and some of the brighter stars are identified in the annotated imageThis image replaces an earlier image that can be seen in the Archives here Vertical FOV (of Full size image) is approximately 149 arc minutes. Full size image scale is about 1.46 arcsec/pix.

Image center is approximately - Equatorial 2000: RA: 19h 43m 09s Dec: +2317'41"


All images and content remain the property of Jim Thommes - copyright 2003 - 2023

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