sponsored by psychohistorian.org
RA: 16h 32m 38.68s
Dec: +78° 11′ 54″
Con: Ursa Minor
Ch: MSA:1046, U2:11, SA:3
Type: galaxy (HII), Sb
Mag: B=12.1, V=?
Size: 3.09′ x 2.57′
Synonyms: H I-280
Discovered in 1797 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "vB, cL, lE, lbM. The greatest brightness confined to a small point."
Listed as No. 185 in Arp's "Atlas of Peculiar Galaxies" (Astrophysical Journal Supplement, vol. 14, 1966.) He remarks "Condensed nucleus. Faint outer arms less curved than inner arms."
A supernova erupted in this galaxy in 1983 (15.1pg)
de Vaucouleurs, G. (1975) Nearby groups of galaxies. In: Kuiper, G. (ed) Stars and Stellar Systems. Volume 9: Galaxies and the Universe. Chapter 14, p557.
Foreground NGC 6503; background NGC 6621.
Brightest members: 6643 ( B(0) = 11.97), 6217 ( B(0) = 12.17), 6340 ( B(0) = 12.21), 6412 ( B(0) = 12.62), 6654 ( B(0) = 12.80).
The RNGC (Sulentic and Tifft 1973) notes that this is a 12.5 mag galaxy. Their coded description reads S,R,HISB,COMPLEXSSTR PD.
Sandage, A. & Tammann, G. A. (1975) Steps toward the Hubble constant. V - The Hubble constant from nearby galaxies and the regularity of the local velocity field. ApJ, 196, 313-328. [1975ApJ...196..313S]
Sandage and Tammann (1975, Astrophysical Journal, 196, 313-328) includes this galaxy in the NGC 6643 Group. Members include NGC 6217, NGC 6340, NGC 6412, NGC 6643 & NGC 6654.
G. de Vaucouleurs ("Galaxies and the Universe", Chapter 14 - Nearby Groups of Galaxies) notes that the five brightest members of the NGC 6643 group are NGC 6643, NGC 6217, NGC 6340, NGC 6412 & NGC 6654. NGC 6503 is a foreground member, and NGC 6621 is a background member.
Houston notes that this galaxy in Ursa Minor is 11th mag, "and I estimate it to be about 1' long. This spiral should be within reach of any scope 8 inches or larger, but on good nights I have found it with a 4-inch."
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "12M; 1.8' x 1.2' extent; bright oblong with little brighter center; axis oriented NNW-SSE; 14M stellar nucleus."
Observing site: Little Bennett Regional Park
[16h 32m 36s, 78° 12m 0s] Small, bright nucleus, uniform elliptical envelop. Sc? B: Sc.
The Messier objects
The Bennett objects
The Caldwell list
DOCdb is still in beta-release.
Known issues, feature requests, and updates on bug fixes, are here:
Found a bug? Have a comment or suggestion to improve DOCdb? Please let us know!
DOCdb is a free online resource that exists to promote deep sky observing.
You could help by sharing your observations, writing an article, digitizing and proof-reading historical material, and more.
Everything on DOCdb.net is © 2004-2010 by Auke Slotegraaf, unless stated otherwise or if you can prove you have divine permission to use it. Before using material published here, please consult the Creative Commons Attribution-Non-Commercial-Share Alike 2.5 License. Some material on DOCdb is copyright the individual authors. If in doubt, don't reproduce. And that goes for having children, too. Please note that the recommended browser for DOCdb is Firefox 3.x. You may also get good results with K-Meleon. Good luck if you're using IE. A successful experience with other browsers, including Opera and Safari, may vary.