CLICK ON IMAGE FOR FULL SIZE VIEW (6397x4357)

Scope: Celestron 9.25 Edge HD 235 mm at f/7; Location: DAA Observatory, Shelter Valley, CA;  Dates:  21, 22 February, 23, 24 March, 2025; Camera: ASI294MM (Baader  LRGB Filters)

Exposure:   Lum 242 x 3.5. minutes (gain-121 2x2), RGB - 54 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 -  Linear fit clipping,  2X drizzle for  Lum) - PixInsight (WBPP).  Noise reduction - NoiseXTerminator (RGB, Lum) - PixInsight.  Non-linear stretching for Lum - PixInsight. RGB combine and stretching, Photometric RGB calibration (SPCC)  - PixInsight. De-convolution - BlurXTerminator (AI4) - PixInsight. Generation of starless  Lum and RGB image for later processing - StarXTerminator (PixInsight).  Lum stars (lower stretch) screened into Lum starless  for star size control - PixInsight.  Luminance  combined to RGB image - Pixinsight. Final finishing  - Affinity Photo.  Annotation - PixInsight, Aladin (Simbad), and Affinity Photo. This image is an LRGB image.  Image processed at 8288x5644 resolution (2x drizzle stacks). Full Field image size is approximately 6397x4357.

North is up in this image. This is NGC 3166 and NGC 3169 forming a galaxy pair  - classified SAB0/a(rs) and SA(s)a pec respectively. NGC 3166 is 71 million light years (by redshift estimate); NGC 3169 is 73 million light years. These galaxies  combine with the nearby smaller galaxy, NGC 3165, to form the Holmberg 173 Galaxy Group. NGC 3166 is the group primary. 

NGC 3169 features tidal streams. They are either due to interaction with NGC 3166 or due to a prior merger of another galaxy.  There are two Dwarf Galaxies in the area, ASK 095840.0 and PGC 29873  (62 to74 million light years). But evidence leans toward interaction with NGC 3166. Also, NGC 3169 has a strong AGN with X-ray emissions but may fall short of Seyfert galaxy energy levels.  

Also in this image field are numerous background galaxies - many in excess of one billion light years in distance. A few Low Surface Brightness (LSB) galaxies are also in the full field image.  The mouse-over starless image shows many of these distant background galaxies (isolated from the Milky Way galaxy stars). There are numerous Quasars as well - the furthest is SDSS J101322.29+033009.0 with a light travel time (Lookback) of 10.79 billion years and redshift of 2.263. These objects, information, and some of the brighter stars are identified in the annotated image.   

The Horizontal Full FOV is approximately 0.66 degrees. Full size, full field image scale is approximately 0.374 arcsec/pix.

Image center approximately - Equatorial 2000: RA: 10h 14m 01s Dec: +03°26'10"