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RA: 13h 29m 52.37s
Dec: +47° 11′ 40.8″
Con: Canes Venatici
Ch: MSA:589, U2:76, SA:7
Type: galaxy (Seyfert 2), Sc
Mag: B=8.8, V=?
Size: 8.317′ x 7.079′
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In the Appendix to the 1912 'Scientific Papers of Sir William Herschel' this object is described as "1783, September 17, 7 feet, 57 power. Two nebulae joined together; both suspected of being stars. Of the most north [I.186] I have hardly any doubt. 7ft, about 150 power. A strong suspicion next to a certainty of their being stars. I make no doubt the 20 ft. will resolve them clearly, as they want light and prevent my using a higher power with this instrument. 1783, September 20, 20ft, 200 power. Most difficult to resolve, yet I do no longer doubt it. In the southern nebula, I saw several stars by various glimpses, in the northern also three or four in the thickest part of it, but never very distinctly. Evening very bad. 1787, May 12. Bright, a very uncommon object, nebulosity in the centre with a nucleus surrounded by detached nebulosity in the form of a circle, of unequal brightness in three or four places, forming altogether a most curious object. I.186 B, R, S, vgbM, just north of the former. 1788, April 29, vB, L, surrounded with a beautiful glory of milky nebulosity with here and there small interruptions that seem to throw the glory at a distance. I.186 cB, pL, a little E, about 3' preceding Mess. 51 and about 2' more north."
Sketched and described.
In the 5th edition of Webb's Celestial Objects for Common Telescopes it is described as "E. of Rosse's wonderful spiral; its wreaths of stars are beyond all but the first telescopes; common ones will only show two very unequal nebulae, nearly in contact, both brightening in the centre: traces of the halo encompassing the larger may perhaps be caught; Smyth could not do more: 'the enigma is another unequivocal mark of the illimitable power of the Supreme Creator!' 9.3-inch speculum showed plainly outer end of spiral, and junction with smaller neb. E. of Rosse, knots . . . a misty spot in finder 3 degrees S.p. Alkaid, at end of Great Bear's tail."
Together with NGC 5195 listed as No. 85 in Arp's "Atlas of Peculiar Galaxies" (Astrophysical Journal Supplement, vol. 14, 1966.) He remarks "faint plumes and extensions from companion."
Astronomical Scrapbook: Spiral structure in galaxies. Sky&Telescope, June, 366.
(Sulentic and Tifft 1973) notes that this is a 10.0 mag galaxy. Their coded description reads SC,B,WD,DKLNS COMPLEX KNY ARMS.
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]
(Astrophysical Journal, 196, 313-328) includes this galaxy in the M51 Group. Members include NGC 5055, NGC 5194 & NGC 5195 .
This galaxy appears on page 26 of "The Hubble Atlas of Galaxies" by Allan Sandage (1961, Washington, DC).
(Astronomical Journal, Vol 66, p566) notes that this galaxy forms a pure pair with NGC 5195 4.4 arcminutes away.
Journal BAA, 35, p159
One of the larger spirals, 12'x6'; takes about 12 inches aperture to show its left-hand spiral structure, and then only because it is previously known; sharp stell.nucleus with many condensations in arms.
Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part I. M.N.R.A.S., 35(5), 159.
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.
5. The nearer groups within 10 megaparsecs
G5. M101 (NGC 5457) Group. (may consist of 2 separate multiplets centred on M51 and M101.
Brightest members: 5457, 5194, 5055, 5195, 5585.
This is a traditional group, but its membership is somewhat uncertain. It is included by van den Bergh in his extended M94 group, but Holmberg and Sersic make it a separate group. ... The major members, then, are M101 (NGC 5457) and its satellites NGC 5204, NGC 5474, NGC 5585 and the wide pair formed by M51 (NGC 5194 and companion NGC 5195) and M63 (NGC 5055); a probable member is NGC 5949, and possibly some outlying systems including NGC 4605, NGC 5907, NGC 6503, A1353 (Ho IV) and A1339 (Ho V). Many dwarfs are concentrated in the region ... Except for NGC 5195 (type I0) all bright members of the group are spirals of type later than Sb and dwarf Magellanic irregulars ... the overall dimensions of the group are 23° x 16°, and agan there is no central condensation.
"! nebula, spiral, nucleus"
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
writes: "This is the famous 'Whirlpool Galaxy', the first galaxy found to show a spiral form. It was discovered by Messier in October 1773, and the intruiging spiral pattern was first detected by Lord Rosse with his giant 6-foot reflector at Parsonstown, Ireland, in 1845. Rosse published his drawing of the object in 1850; it seems that he observed the galaxy previously with a 3-foot telescope and has missed the spiral pattern. Sir John Herschel, with his 18-inch reflector, had described a 'very bright round nucleus surrounded at a distance by a luminous ring.' ... [it is] of the 8th magnitude visually and about 10' in apparent diameter. As one of the nearest and brightest of the galaxies, the Whirlpool is of great interest to all observers, though very little detail may be seen except in fairly large telescopes. A good pair of binoculars will show the object on a clear dark night, and a 2-inch glass will reveal a hazy patch of light with a brighter centre. With a 6inch glass the central nucleus appears prominently and dominates the misty glow of the system. The spiral form may be glimpsed, under the best conditions, and with some uncertainty, in an 8-inch telescope. In a 10-inch it may be held unmistakably when atmospheric conditions allow, and in a 12-inch the spiral coils begin to resemble the familiar photographs which have graced countless astronomy texts. ... The actual nucleus is about 2.7 arcseconds in diameter and appears nearly stellar."
Notes that with 30cm he sees "two bright round hazy spots 5' apart in pa 20 degrees, resp about 2' and 1' across."
Notes: "Messier discovered it in October 1773 and saw two nebulae 'each with a brilliant centre' and their 'two atmospheres touching.' The brighter object is M51 itself, while its slightly fainter companion, NGC 5195, lies just to its north. ... Though his 4-inch refractor, John Mallas reported seeing a possible trace of M51's spiral arms and also the connecting bridge of material between the main galaxy and its companion. Mallas, however, suggests that his knowing how this system appears on photographs may have influenced his observations. Working with a 10-inch f/5 reflector in the clear skies of Arizona, Ron Morales succeeded in glimpsing the bridge only once when conditions were excellent. The spiral arms, however, have been quite visible to him for years with a variety of telescope magnifications. In Kansas during the 1950's, my 10-inch f/8.6 at 60x revealed the brighter spiral arms, but the bridge was much more elusive. Three years ago I carefully examined M51 with a 5-inch apogee scope at 20x. As might be expected, the two nuclei were bright but there was no hint of the spiral structure."
Houston notes that the spiral arms can be readily seen in an 8-inch and are unmistakable in a 12-inch. He adds: "Experienced observers under good skies have reported the spiral pattern with 6-inche apertures, and some, including me, have even glimpsed it with a 4-inch." Larger apertures are needed to show the bridge of material between M51 and its companion.
MacRobert calls it "one fo the amateur showpieces of the sky ... for all that, M51 is not as grand a sight as its reputation (and photographs) imply. It is only one fifteenth the diameter of M31 and only a hundredth as bright ... In my 6-inch reflector as 45 power under moderately light-polluted skies, M51 and its companion are a pair of hazy gray glows with brighter centres. They are just 4' apart. Of the two, M51 looks much larger and rounder and its centre is brighter ... at 200x the companion shows a bright, almost stellar nucleus that is definitely more concentrated than that of the main galaxy. Moreover, the companion seems to suffer a sharp cutoff in brightness just east of its nucleus, as if peering out from behind a dark dust cloud - an impression that photographs confirm. An 8-inch telescope under a godo sky begins to show traces of spiral or ring structure ... a 17-inch scope makes the spiral shape obvious."
writes: "This fine face-on spiral is the large component of M 51, the Whirlpool Galaxy, the smaller companion being the irregular galaxy NGC 5195. In small telescopes M51 looks like two fuzzy spots next to each other. In a 6-inch telescope they appear different, with the spiral a softly defined disk, and the other seen as a bright spot with a brighter nucleus. In a 10- or 12-inch or larger we begin to see signs of the spiral arms looking just like a revolving firework, with several small stars seen against the arms. The 'bridge' that connects NGC 5194 and 5195 is a faint one, and its visibility is a good indication of good atmospheric conditions and good telescope optics."
, California reports seeing spiral structure in M51 and M101 with a 10-inch f/5.6 at about 56 power. Though they observed from an altitude of 6750 feet, there is considerable sky glow." (Sky&Telescope, November 1973, p344)
(e-mail: email@example.com, web: http://www.geocities.com/CapeCanaveral/3693/)
Instrument: 10-inch Schmidt-Cassegrain reflector Location: Mt. Pinos, California, US
Light pollution: none Transparency: excellent Seeing: excellent
Time: Sat Jun 7 10:00:00 1997 UT Obs. no.: 147
What a sight. This large galaxy gumped out under the cool clear skies at @ 104X. I could easily easily see the spiral arms even under low power. It's comapion, NGC 5195 was also easily visable under these beautiful skies. The two were rather bright due to the great seeing. Two beautiful objects.
(e-mail: firstname.lastname@example.org, web: http://www.west.net/~jbc/)
Instrument: 8-inch Dobsonian reflector Location: Carpinteria, CA, USA
Light pollution: light Transparency: good Seeing: good
Time: Tue Jun 24 05:45:00 1997 UT Obs. no.: 153
With a fair amount of indirect glare from the neighbor's patio lights and my eyes not yet completely dark-adapted, M51 and NGC 5195 (the companion) were easy at 49x as a pair of fuzzy cores, one bigger and brighter, both with an extended halo that was fairly easy with averted vision, though M51's halo was much larger. I thought I saw a hint of structure in M51's halo, but nothing I could call spiral structure. 49x seemed to give a better view than 122x.
Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "8.1M; 11' x 8' extent; the "WHIRLPOOL"! large, round spiral with stellar nucleus; spiral arms readily visible in 8-in. and larger scopes; 12M star just S of nucleus; IRR GAL N5195 (11M; 2' x 1.5' extent) is a satellite system of M-51 due N at end of very soft NE-side filaments; !good supernova prospects! see photos at HAG-26 and 31; EL GAL N5198 (12.7M; 2' diameter) soft blob 30' to S; and a little E."
POSS: 1988 15cm obs details confirmed, but halo of -95 not esp flattened on S side twd -94. pair: 11,11.5; 47"; pa47.
ApJ Suppl 38,147 has pe seq: brtr * of wide pair: V=11.24/1.00.
6cm - nice, fairly lg. -94 has a *ar nuc, sm core, than nice halo w/rel well-def edges. on N it touches -95, which is quite sm, sl condensed.
- in dk sky pair easy @ 50x. -94 has mottly halo, not much brtr to center, then sm br core and *ar nuc. -95 is much smlr, broadly concen.
7cm - two br gxs in contact @ 30x, partic f extn on E side of -94 leading up to -95. nucs sim-br, -95s sl fntr, and both sim in size. 50x: -94 nrly circ w/wk even concen (but at modhisfcbr) to circ core, which has strong even concen to sub*ar nuc. -95 seems roughly circ w/strong even concen to sub*ar nuc. at 50x there seems to be a narrow dk gap btwn the two gxs. can't see m13.5 * SE of -94. BS, 15Apr1993, Anderson Mesa.
15cm - fairly interesting: two br cores could be seen w/outlying haze. -94 looked 6'x5', while -5 is 3'x2'. BS notes that it is difficult to tell which is brtr but easy to distinguish by sizes.
- in dk sky, really cool. distinct. fairly lg center that dominates surroundings; arms fntr, 10' diam. no bridge to -95. -94 has gran nuc;
-95 is diffused. BS notes arm on SE side of -94.
- br pair not touching. 30x: both nucs prominent, seem sim-br; that of -94 sub*ar, -95's *ar. sup m13.5 * in SW side clr @ 50x, as is m13.5 * off to SE. 80x/140x: -94 seems like vlg annular pn w/br cen *: arms incipiently discerned; br arc in arm in NE quad (opposite embedded m13.5 *), interarm gaps pop in and out. 165x shows br circ core w/mod br *ar nuc. at this power -95 seems still to be not touching, connecting arm not vis. *ar nuc more consp here than in -94. core bar-like, aligned twd center of -94, brtr on side away from lgr gx. core boundary sharply defined on E side, where it cuts closely to nuc. wk oval halo perpendicular to core, flattened on side facing -94. wide pair (45" sep) in fld 10' SE is nice @ 30x, but uninteresting at higher powers. BS, 26Mar1988, Anderson Mesa.
20cm - 44x: two br obvious glows, 5:3 brightness ratio. long attention shows 5' circ haze behind -94. -95 5' from -94. -95 oval w/maj axis perpendicular to line connecting the two. both have *ar nuclei; no arms seen. SKJ.
25cm - sketch in notes. BS, Slate Mtn.
30cm - great, of course. spiral nature evident in both arms. Ern arm is the brtr, unwinding clockwise. its brtst portions are on SE & NE, after which it disappears. Wrn arm has one big brtning on SW, w/m12.5 * on inner ] side. core looks optically deep, glowing internally like an unres gc. 5'.5 diam overall. -95 uneven w/*ar nuc off-center to SE. dk blob intrudes on SE, w/separated part of halo. luminosity profile of -94 in notes.
1.1m - incredible!! two spiral arms vis distinctly and in their entirety. first originates at core (1'.8 diam) on SSW, winding clockwise, through E clear around to W. best condens on SE & NE portions, as well as minor condens on NNW. second arm originates on NNE. not as many condens as first arm. it spirals evenly outward to SE, where it deviates from spiral, continues passing almost tangent to inner arm, then reaches out to -95. best condens on SE and from W to SW. this arm reaches clear to core, while arm #1's junction is less distinct.
-95: br 12" nuc is surrounded by 2' halo. core seems elong in pa25, but this may be due to lg dk area on E side. past dk area, a fnt luminosity can be seen where arm #2 from -94 enters. CBL, Apr1976(?), Hall telescope, Anderson Mesa.
12-inch f/10 SCT (95x/52.8′, 218x/23.1′)
Messier 51 contains two misty clouds, which with a magnitude of 8 clearly display the bright cores of both the galaxies in an outstanding accompany star-field. With excellent seeing on the 28th April 2006 I had the best in SA of this object. NGC 5194 the bigger galaxy displays a soft round haze with visible darker spiral moulted areas. Although both nucleuses is outstanding bright NGC 5194 is however fainter than NGC 5195, which is just a small round compact haze but surely outstanding.
Observing site: Pinnacles overlook
[13h 29m 54s, 47° 12m 0s] Very good tonight, scraping the zenith. and more spiral structure and mottling was noticed than usual, when it's seen rising in the north east. A magnificent object.
Observing site: Pinnacles overlook
[13h 29m 54s, 47° 12m 0s] 80x: This is a glorious galaxy in dark skies. Even with an 8 inch , the spiral structure is glimpsed. NGC 5195 appears as a bright patch next to M51.
Observing site: Pinnacles overlook
[13h 29m 54s, 47° 12m 0s] Never seen it better! Spiral arms easily seen. Magnificent.
Observing site: Little Bennett Regional Park
[13h 29m 54s, 47° 12m 0s] Found the 14mv supernova. Nice! Confirmed: UniverseToday.com.
The Messier objects
The Bennett objects
The Caldwell list
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