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Holmberg 218, Arp270 - Galaxy Pairs and Mahtessian 98 Galaxy Group



Scope: Celestron 9.25 Edge HD 235 mm at f/7, Location: DAA Observatory, Shelter Valley, CA,   9, 13 March 2024  Camera: ASI294MM (Baader  LRGB Filters)

Exposure: Luminance - 117 x 3 minutes (gain-121 2x2) , 93 x 3 minutes (gain-121 1x1);   RGB - 44 x 2 minutes  each (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  Clipping Rejection) - PixInsight (WBPP).  Mure Denoise - PixInsight.  Non-linear stretching - PixInsight. Gradient Correction - PixInsight.  Curves, Levels, RGB combine, Luminance layering - PixInsight. Generation of starless Luminance image for later processing - StarXTerminator. Photometric RGB calibration (SPCC) - PixInsight.  De-convolution - BlurXTerminator.  Final finishing  - Affinity Photo.  Annotation - PixInsight, Aladin (Simbad and NED), and Affinity Photo. This image is a  LRGB with luminance layering.  Image processed at 4131x2809 resolution. Final Image size is approximately 4807x3234.

North is up in this image. This image shows a galaxy double - double. The first pair is Holmberg 218 (NGC 3430,  3424); the second pair is  Arp 270 (also Holmberg 215, NGC 3395, 3396). These four galaxies are in the same distance range -  from 82 to 89 million light years - making them potentially grouped.  As such, this foursome are also members of other galaxy groups - one of those is the Mahtessian 98 galaxy group (also grouped in Temple et al. 2MASS redshift data groupings of 2016 and 2018). Other galaxies in this field of note are NGC 3413 and IC 2608. This field also has  many background galaxies that are visible in the full size image. Finally, there are a number of visible quasars in this image - the furthest has a redshift of 3.304 and a light travel time (Lookback) of 11.77 billion years.   These objects, information,  and some of the brighter stars are identified in the annotated image  Horizontal FOV is approximately 40.1 arc minutes. Full size image scale is approximately 0.58 "/pix. 

Image center is approximately - Equatorial 2000: RA: 10h 51m 05s Dec: 3254'27" 


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

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