Arp 217 / Bow and Arrow Galaxy / NGC 3310

NameBow and Arrow Galaxy
Designation(s)Arp 217, NGC 3310
Object Type(s)Galaxy
Relevant Catalog(s)All (Chron), Arp, NGC
Arp CategoryGalaxies with adjacent loops
Obs. Lat/Long42° 17', 073° 57'
ConstellationUrsa Major
Date and Time Observed2025-05-11 22:26:00
InstrumentEdgeHD 8" w/f7 reducer-1,422mm FL
CameraPlayer One Apollo-M Mini
Image DetailsUp is 90.5 degrees E of N. Transparency: Fair. Seeing: Fair. Total integration time was 32m15s. Exposures 15s@300g, UV/IR Cut Filter. Dithered and recentered in SharpCap. No guiding.
DescriptionThe first observation following a clear day, but with a full moon. As it turned out clear enough. This has a very bright galactic core, and is another William Herschel discovery from 1789.

Arp categorizes this as "Galaxies with adjacent loops", and notes that the main arc (the bow) consists of H-alpha. This is normally associated with start formation, and modern commentators classify this as a post-merger "starburst galaxy". "Starburst galaxies" have a star formation rate at least 10x the Milky Way's. They are often characterized by funky structure, as we see in this case. Note, particularly in the inverted image, there is a pretty convincing arrow crossing the bow towards the left end of the arc. Certainly in my inverted image, it appears that at least two galactic cores abut each other: a big central core, viewed top down and therefore nearly round, and the second, to the upper right, viewed edgewise. There appear to be a set of nodules to the left of the core: star birthing areas? Dwarf galaxies never absorbed? Best viewed in the positive image with some reference to the inverted. All on all, a fascinating set of structures which appear to be the result of disruption.
Catalog Links
 All Listings 
Featured Image