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NGC 1491 "Fossil Footprint"



Scope: Celestron 9.25 Edge HD 235 mm at f/7; Location: DAA Observatory, Shelter Valley, CA;  Dates:  8, 11 November 2023; Camera: ASI294MM (Baader  Ha OIII RGB Filters)

Exposure: Ha 80 x 4 minutes (gain-160 2x2) ,  OIII 84 x 4 minutes (gain-160 2x2), RGB - 36 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) - PixInsight (WBPP).  TGV Denoise (RGB) and MMT  (Ha, O3) - PixInsight.  Non-linear stretching for Ha and OIII - PixInsight.    RGB combine and stretching, Photometric RGB calibration (SPCC)  - PixInsight. Generation of starless Ha, OIII, and RGB image for later processing - StarXTerminator  (PixInsight.)  De-convolution - BlurXTerminator (AI4) - PixInsight.  Ha and OIII color mapping is a modified HOO palette of the starless stacks - PixInsight.  RGB star image is screened into the Ha and O3 narrow band starless construction - Pixinsight. Final finishing  - Affinity Photo.  Annotation - PixInsight, Aladin (Simbad), and Affinity Photo. This image is a  modified HOO mapping with RGB stars.  Image processed at 8288x5644 resolution (2x drizzle stacks). Final crop Image size is approximately 7855x5644.


North is up in this image - it is a close up of  NGC 1491- the "Fossil Footprint" nebula. NGC 1491 is also known as LBN 704 and Cederblad 25. It is loosely associated with LBN 705, LBN,706, and Sh2-206.  The latter identification, Sh2-206 covers the full field of this image (and more).  NGC 1491 is an emission nebula structure  with most of the Ionization energy coming from the  star BD+50 886 (TYC3339-339-1).  Distance of NGC 1491 is about 10,700 light years.  There is a background galaxy that shines through this emission structure - LEDA 2798535, but there is scant data on this galaxy.  These objects, information, and some of the brighter stars are identified in the annotated image.  The Horizontal FOV is approximately 0.635 degrees. Full size image scale is approximately 0.291 arcsec/pix.

Image Center approximately - Equatorial 2000: RA: 4h 03m 33s Dec: 5118'46"


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

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