NGC4631 & NGC4656 – The Whale and the Hockey Stick


* Acquired 2016-12-02 - 2017-03-04 
* RGB acquired from TriStar Observatory TinyObs through 2017-02-04  Bortle class 6-7
* Lum acquired during the 2017 /r/Spaceonly Imaging Party in Marathon, TX, 2017-02-26 - 3017-03-04  Bortle class 2
* 40h 5m of integration
* Equipment
	* Stellarvue SV80ST
	* Astro-Physics Mach-1 GTO
	* Atik 414EX
	* Orion 1.25" LRGB Filters
	* QHY5-L II Guidecam
	* All processing in PixInsight

From Wikipedia

NGC 4631 (also known as the Whale Galaxy or Caldwell 32) is a barred spiral galaxy in the constellation Canes Venatici. This galaxy’s slightly distorted wedge shape gives it the appearance of a herring or a whale, hence its nickname. Because this nearby galaxy is seen edge-on from Earth, professional astronomers observe this galaxy to better understand the gas and stars located outside the plane of the galaxy.

NGC 4631 has a nearby companion dwarf elliptical galaxy, NGC 4627. NGC 4627 and NGC 4631 together were listed in the Atlas of Peculiar Galaxies as an example of a “double galaxy” or a galaxy pair.

NGC 4631 and NGC 4627 are part of the NGC 4631 Group, a group of galaxies that also includes the interacting galaxies NGC 4656 and NGC 4657. However, exact group identification is problematic because this galaxy and others lie in a part of the sky that is relatively crowded. Estimates of the number of galaxies in this group range from 5 to 27,and all studies identify very different member galaxies for this group.

My primary goal in selecting this target for the 2017 /r/SpaceOnly Imaging Party in Marathon was to
be able to go deep enough to capture the stellar stream eminating from NGC4631. I knew
there was no chance of capturing Lum frames long enough from home.

Unfortunately, Marathon’s weather wasn’t as cooperative as we’d hoped, and I just didn’t get enough data to push the stretch where I wanted. While I absolutely captured the stream :


the SNR just isn’t high enough for my mediocre processing skills to do it justice. It’s “there” in the final result, but only just barely.

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