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NGC 4631 and 4656 in Canes Venatici



Scope: Explore Scientific MN152 Maksutov Newtonian at f/4.8, Location: DAA Observatory, Shelter Valley, CA,  14th, 30th March 2019  Camera: Atik 383L (Astronomik Gen 2  LRGB Filters)

Exposure: Exposure:  20 x 15 min (1x1 bin) exposure with IR/UV Block filter, 8 x 5 min (2x2 bin) RGB exposures.

Processing: Data Collection -  Sequence Generator Pro (as FITs).  Exposure calibration, LRGB registration, and stacking (Median combine -  Winsorized Sigma Clipping) - PixInsight.  LRGB channel registration, equalization and gradient removal - PixInsight.  Curves, Levels, RGB combine, Luminance layering - PixInsight. Final finishing  - Photoshop.  RGB calibration - eXcalibrator. Annotation - PixInsight, Aladin (Simbad and NED), and final touchup /additions in PhotoShop. This image is a  RGB combine with Luminance layering.  Images processed at 3354 x 2529 resolution. Final Image size is approximately  2800 x 2100.

North is up in this image. There are four major galactic objects in this image - two are predominant. In the upper right is NGC 4631 popularly known as the Whale Galaxy with a close neighbor NGC 4627.  In the lower left is NGC 4656 and NGC 4657 known as the Hockey Stick or Crowbar Galaxy. These galaxies are believed to be interacting. Since 2010 there has been high interest in this region. There have been a number of nearby Dwarf galaxies discovered  by amateur and professional astronomers; up to twelve have been surveyed and discussed since then. This image resolves six of the twelve ([TCK2017 HSC1, 2, 5, 6, 7, 8] ).  There is also discussion of stellar streams resulting from a hypothesized progenitor dwarf that interacted with NGC 4631 in the distant past  (dwarf now dispersed). These streams are barely resolved in this image - running from about image center toward the upper right through NGC 4631.  These objects are shown in the annotated image; this field lies in Canes Venatici near the Coma Berenices border.  This image replaces an earlier image that can be seen in the Archives here.   Horizontal FOV is about 88'. Image resolution on the full size image is about 1.88 arcsec/pix. 

Image center is approximately - Equatorial 2000: RA: 12h 42m 31s Dec: +3226'23" 


All images and content remain the property of Jim Thommes - copyright 2003 - 2019

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