sponsored by psychohistorian.org
RA: 12h 35m 26.58s
Dec: +14° 29′ 45.1″
Con: Coma Berenices
Ch: MSA:725, U2:194, SA:14
Type: galaxy (AGN LINER-type), SBb
Mag: B=11.5, V=13.57
Size: 5.248′ x 4.365′
Since the publication of the third and final part of Messier's catalgue in 1784, the identity of Messier 91 has been a mystery. The Texan amateur astronomer W. C. Williams has suggested that NGC 4548 is Messier 91, a proposal that has been accepted by Mallas and Kreimer, authors of "The Messier Album". Other possibile candidates include NGC 4571, NGC 4579 & NGC 4689.
Williams, W.C. (1969) Letters [M91 = NGC 4548]. Sky&Telescope, Dec, 376.
Synonyms: H II-120
Discovered in 1784 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "L, r."
The RNGC (Sulentic and Tifft 1973) notes that this is a 11.5 mag galaxy. Their coded description reads BSB,2DIFBDWD ARMS A FEW KNS.
This galaxy appears on page 48 of "The Hubble Atlas of Galaxies" by Allan Sandage (1961, Washington, DC).
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "11.9M; 4.5' x 3.5' extent; soft fuzzy with brighter center; look carefully for very soft halo; it's larger than you think! labelled in Tirion as M-91; Owen Gingerich concurs; !good supernova prospect! see photo at HAG-48."
Lick: bar in pa60, overal pa150.
7cm - mod f modlosfcbr glow @ 50x. halo circ but core elong ~E-W. wk even concen up to core, which is wk-sharply brtr and has *ry texture. BS, 15Apr1993, Anderson Mesa.
15cm - 2'.5x2', even patch w/smlr condensed nuc.
25cm - 180x: fairly br, elong E-W, 2'.5x1'.5. rises smoothly to sm circ core and *ar nuc.
Observing site: Pinnacles overlook
[12h 35m 24s, 14° 30m 0s] A large, face on Sc, with a bright middle. Burnham: an SBb. Wiki Sky lists this as M 91.
Sky Conditions:The fainter parts of the Milky Way are barely visible.Haziness only visible on the horizon.Atmosphere stable with little interference.
This bright galaxy's oval like structure is clearly seen at a low magnification of 57*and 75*.M91's circular shape with its diffuse spiral arms are on the brink of visiblity.Around the far outskirts of this galaxy I have found some areas of uneven brightness.This galaxy measures 4'* 3'.The central nucleus of this galaxy is brighter compared to the far outskirts of this galaxy.
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.