sponsored by psychohistorian.org
RA: 12h 30m 36.71s
Dec: +41° 38′ 26.6″
Con: Canes Venatici
Ch: MSA:611, U2:75, SA:7
Type: galaxies (interacting), Sd
Mag: B=10.1, V=?
Size: 6.606′ x 3.548′
Synonyms: H I-198
Discovered in 1788 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "Two. The southern [NGC 4485] vB, vL, iE. The northern [NGC 4490] B, pS, iF; distance 1.5'."
In the 5th edition of Webb's Celestial Objects for Common Telescopes it is described as "long, easily resolvable. d'Arrest, a small faint nebula N.p."
"nebula, elongated at 135°, 1.0' x 0.3'; B at centre; spiral?"
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
Burnham calls it a 10.1 mag spiral galaxy in Canes Venatici, measuring 5.0' x 2.0', which is very bright, very large and much elongated. He notes that the galaxy is pear-shaped and bears the nickname Cocoon Galaxy.
NGC 4485 lies 3' to the north. Together with NGC 4485 listed as No. 269 in Arp's "Atlas of Peculiar Galaxies" (Astrophysical Journal Supplement, vol. 14, 1966.) He remarks "resolution into knots, emission regions and dust lanes only"
(Sulentic and Tifft 1973) notes that this is a 11.0 mag galaxy. Their coded description reads EL,IRR,HISB,VKNY.
(1961, Astronomical Journal, Vol 66, p566) notes that this galaxy forms a pure pair with NGC 4485 3.5 arcminutes away.
by Jim Lucyk: Sky&Tel. 7/82 p106, Sky&Tel. 11/88 p465, Astronomy mag. 8/82 p84.
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.
This is part of the complex region described as the Canes Venatici (M94) cluster by van den Bergh and as the UMa II group by Sersic. ... a dozen bright objects (NGC 3769 3769A 3949 4051 4088 4111 4143 4242 4485 4490 4625 4618), mainly late-type spirals and irregulars (NGC 4111 and 4143 are lenticulars) form an elliptical core area measuring 15° x 8° ... the overall dimensios of the cloud are increased to 22° x 12° is several probable or possibly outlying members such as NGC 3675 4627 4631 46564657 4800 and the dwarf systems NGC 4025 4288 are included.
A supernova erupted in this galaxy in 1982 (16.0v).
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]
(1975, Astrophysical Journal, 196, 313-328) includes this galaxy in the Canes Venatici II Cloud. Members include NGC 3675, NGC 4051, NGC 4485, NGC 4490, NGC 4627, NGC 4631, NGC 4656 & NGC 4657.
Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "10.1M; 5' x 2' extent; NW-SE-oriented oblong; soft with bright, non-stellar core; 15M star on W end; 35' WNW of 4.5M Beta CVN; IRR GAL N4485 (12.5M; 1.3' x 0.7' extent) 4' to NNW; like M-51 and friend! good supernova prospects."
writes of NGC 4490 and NGC 4485 as "These colliding galaxies are easy to locate just 2/3 degree northwest of Beta Canum Venaticorum. NGC 4490, with a total visual mag of 10, is the first you'll see. Its fairly easy in the 6-inch, a gray glow elongated northeast-southwest."
POSS: m10 * 5'.1 S.
6cm - elong, 1'.5 long.
7cm - mod br smooth lenticle nr beta CVn @ 30x. 50x: elong in pa100, length
1.5x sep to m11.5 * SE, 2:1 ratio. classic mod even concen to ill-def
oval core and wkly brtr nuc. BS, 15Apr1993, Anderson Mesa.
15cm - 5'x2' w/ little cen condensation but BS notes irreg patches, notably a
lgr diffuse patch and a smlr dense one. [could this be an obs of both -85
- fine br un= pair of gxs. -90 much brtr/lgr: 7'x2'.5 (seems longer than
distance to m10 * S). mottly w/patches and *ings @ 165x. NE-facing flank
flatter, oval core offset twd it. wk even concen. core has a few *ings,
one is prob nuc. NW tip extends farther from center, more pointed than
rounded SE extremity; tip occas seems to curl twd -85. BS, 20Mar1988,
25cm - elong ESE-WNW. lg & br, 5'x1'.5. sm cen bulge. axial br dots nr center.
30cm - 6'x4'. on N is dk band along the axis N of nuc. on SW 4' is suspected neb
w/45" core and no concen, this for -90 itself. [say what?]
12-inch f/10 SCT (95x/52.8′, 218x/23.1′)
NGC 4490, displays a lovely oval, very slowly getting brighter to a not outstanding nucleus. Elongated in a NW-SE direction. Around 2' to the north of NGC 4490, NGC 4485 can be seen as a soft fleck of light. Reminds me of a Rhino animal and little infant on its side, nice round to oval small glow 12" S/C – 218x. Nice triple star to the north in the field of view 12" S/C - 95x.
Observing site: Little Bennett Regional Park
[12h 30m 36s, 41° 38m 0s] A bright, almost edge on Sc? Envelope mottled. A very interesting galaxy. (Sc: Burnham)
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.