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RA: 12h 22m 54.95s
Dec: +15° 49′ 19.5″
Con: Coma Berenices
Ch: MSA:701, U2:193, SA:13
Type: galaxy (AGN), Sc
Mag: B=10.6, V=?
Size: 7.585′ x 6.165′
In the Philosophical Transactions, 1814, William Herschel described it as "a nebula of about 10' in diameter, but there is in the middle of it, a small, bright cluster of supposed stars."
Sketched and described.
Four supernovae erupted in this galaxy; 1901 (12.1p), 1914 (14.0p), 1959 (17.5p), 1979 (11.0v)
(Sulentic and Tifft 1973) notes that this is a 10.5 mag galaxy. Their coded description reads SC,B,SC,2BWDKNY ARMS.
G. de Vaucouleurs ("Galaxies and the Universe", Chapter 14 - Nearby Groups of Galaxies) notes that the five brightest members of the Virgo I (S) group are NGC 4321, NGC 4501, NGC 4254, NGC 4569 & NGC 4579.
This galaxy appears on page 28 of "The Hubble Atlas of Galaxies" by Allan Sandage (1961, Washington, DC).
"nebula, B nucleus, spiral?"
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
Remarks, p.217: "the spiral structure of this nebula is not well shown on A1875 having an exposure of 62 minutes."
Notes that this "is a large diffuse luminous haze about 4' across, rising broadly and then suddenly to a small bright nucleus with no visible structure." He notes that from his location, M100 culminates at 35 deg, and adds: "I see them very easily with 10.5cm."
In 1972 Houston wrote: "Looking at a galaxy, one sometimes gets the feeling that a little more aperture would show the stars. Such a case is the 10th mag broadside system M100, which is about 5' in diameter." Working with his 6-inch refractor and noting that this object brightened from attenuated edges towards the centre, Smyth declared that M100 'is therefore proved to be globular.' But with Lord Rosse's 6-foot mirror no stars were seen, and M100 was characterized with one word: 'Spiral'."
Notes that it "has been called the brightest galaxy in the Virgo Cluster. It appears as a large haze 6.9' x 6.2' across. In 4-inch or larger aperture telescopes, two major arms are seen wrapped around the nucleus. M 100 has produced several supernovae, with such events taking place in 1901, 1914, 1959 and 1984. A typical supernova at this distance reaches about 12th magnitude, easily seen in 8-inch or larger aperture telescopes."
Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "10M; 7' x 6' extent; soft, round, mottled glow with distinct central condensation; two 14M stars 1' each to SW and ESE; see photos at HAG-28-31; faint SP GAL N4312 (12.5M; 2.6' x 1.6' extent) is a very gentle spindle 17' to SSW just past 10M star."
33cm plate: * 2'.7 SE. br patch NW is sector of spir arm.
UBV for fld *s in PASP 93,36.
T&B: * NW V=13.0.
6cm - nice, smoothlu textured w/little concen except for a f non*ar nuc. elong in pa110, 4'x3' overall.
7cm - br, mod lg @ 30x. 50x: sl oval, elong ~E-W, halo reaches 2/3 distance to m13 * off NW side. mod broad concen to sm brtr core w/o sharp nuc. BS, 15Apr1993, Anderson Mesa.
13cm - vbr oval elong ESE-WNW. uniformly br halo and vsm much brtr core. BS, 7Feb1984, USNO.
15cm - 5' diam, broad, rising gradually to a sm brtr core. at times the neb is gran. some f *s on E side.
25cm - 5'x4', elong SE-NW. br core. muich of area seems curdled and mottled. sev *s noted in neb.
30cm - 149x: pretty f, elong pa120, 3'x1'. 238x: 4'.5x3' in pa120. not well concen but w/sm br 20" core. core is contrarily oriented in pa60, with little wings on NE & SW. sev *s assoc just in edge of extensive uneven halo. sketch in notes.
- 5'x4' in pa115. m13 * on SE edge. core seems vsl oval in pa80, no nuc evident. consp br patch nr uoter edge of halo NW of center. a few other br & dk spots/*ings and a couple of *s over gx. BS, 7Feb1984, USNO.
Alldays (22.50S, 20.12E, 770m).
12-inch f/10 SCT (218x)
This is a pretty large Coma galaxy member, which show off as a large glow. HP show hints of wheel structure which I suspect with averted vision. 16" show two sweeping irregularities extending from core. Sharp small star like nucleus, very hazy on the edges. Will go back and made a sketch.
Observing site: Pinnacles overlook
[12h 22m 54s, 15° 49m 0s] An almost face on Sc. It has a bright nucleus, and a fainter, uniform disk, with the 24.5mm Ultrawide.
Sky Conditions:The fainter parts of the Milky Way are barely visible.Haziness only visible on the horizon.Atmosphere stable with little interference.
This galaxy has a circular shape with prominent spiral arms which are clearly observed with a brilliant oval nucleus strongly condensed.This galaxy measures 8.2'* 2.7'.The central nucleus of this galaxy grows brighter compared to the far outskirts of this galaxy.
The Messier objects
The Bennett objects
The Caldwell list
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