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[M 11]

Messier 11

Observations and Descriptions

Discovered 1681 by Gottfried Kirch.

Messier: M11.
May 30, 1764. 11. 18h 30m 23s (279d 35' 43") -6d 31' 01"
Cluster of a great number of small stars, near the star K of Antinous [ Scuti], which one can see only in a good instrument; with an ordinary telescope of 3 feet [FL] it resembles a comet: This cluster is mingled with a faint glow; in this cluster there is a star of 8th magnitude. Seen by Kirch in 1681. Phil. Trans. No. 347, p. 390 [Halley]. It is reported on the English Great Atlas. (diam. 4')

[Mem. Acad. for 1771, p. 439 (first Messier catalog)]
In the night of May 30 to 31, 1764, I have discovered, near the star Kappa of Antinous, a cluster of a large number of small stars which one perceives with good instruments; I have employed for this a Gregorian telescope which magnifies 104 times. When one examines it with an ordinary [non-chromatic] refractor of 3 & a half feet [FL], this star cluster resembles a comet; the center is brilliant, there is among the small stars one star of eighth magnitude; two other, one of the nineth & one of the tenth: this cluster is intermixed with a faint light, & its diameter is about 4 minutes of arc. I have determined its position in right ascension as 279d 35' 43", & its declination of 6d 31' 1" south.
Mr. Halley reports in the Philosophical Transactions, no. 347, page 390,, that Mr. Kirch did the discovery of that nebula in 1681, that it precedes the right foot of Antinous, that it isn't itself anything but a small obscure patch, & that it contains a star which rather shines when traversing it, what gives it more light, its [ecliptical] longitude was in the [sign] Capricorn at 9 degrees [279 deg]; with 17d 1/2 northern latitude. That nebula was consequently observed by Derham, (Philosophical Transactions, no. 428, page 70) he reports, it follows a translation of his Memoir [here actually a transcript]: "Five of these six I have carefully viewed with my excellent eight Foot Reflecting Telescope, and find them to be Phaenomena much alike ; all except that preceding the right Foot of Antinous, which is not a Nebulose, but a Cluster of Stars, somewhat like that which is the Milky-Way." Mr. le Gentil also mentioned it in the Memoirs of the Academy of 1759, page 469. M. de Chéseaux has employed a Gregorian telescope of two feet, & a refractor of 25 feet [focal] length for examining that nebula in Antinous, which he had recognized to be a prodigious cluster of small stars; M. le Gentil made use of a [reflecting] telescope of 3 feet & an ordinary [non-achromatic] refractor of 20 feet [focal] length, making at least the same effect as the [reflecting] telescope & the refractor of M. de Chéseaux; he recognized that theat nebula was very bad terminated at its preceding border, the sort which imitates rather well at this side, the coma of a Comet; he didn't perceive in the middle that a single bright star which one doesn't perceive, he said, but with a refractor of 8 feet. M. le Gentil thinks M. de Chéseaux has indeed confused that nebula with a neighboring cloud which contains a prodigious number of small stars.
[p. 455] 1764.May.30. RA: 279.35.43, Dec: 6.31. 1.A, Diam: 0. 4. Cluster of a large number of small stars, near the star k [should be "Kappa" according to above text] of Antinoüs.

Halley (1716): No. 5, Nebula in Antinous (Scutum)
[in Phil. Trans. XXIX, 390 (1716)] A Fifth was discovered by Mr. G. Kirch in the Year 1681, preceding the Right Foot of Antinous: It is of its self but a small obscure Spot, but has a Star that shines through it, which makes it more luminous. The Longitude of this is at present [Capricorn] 9 deg. circiter, with 17 deg 1/6 North Latitude.

[in Phil. Trans. XXXVIII, 70 (1733)] Five of these six [nebulae in Halley's list] I have carefully viewed with my excellent eight Foot Reflecting Telescope, and find them to be Phaenomena much alike ; all except that preceding the right Foot of Antinous, which is not a Nebulose, but a Cluster of Stars, somewhat like that which is the Milky-Way.

De Chéseaux: De Ch. No. 14.
Finally, a wonderful cluster of small [faint] stars, near one of the feet of Antinous [now in Scutum], of which RA is 279d 21' 10" and southern Dec is 6d 32' 20"; it is abount 4 1/8 ' in diameter.

Bode: Bode 62.
A nebulous star cluster near a nebula.
On October 8 [1774], I looked for the position of the already known nebulous star, west of the foot of Antinous, which actually forms a triangle with the stars k and l at Sobieski's Shield (Sct), and measured its separation from these stars, as shown in the fifth figure.

Koehler: Koehler No. 20
[Nebula] In Antinous [now Scutum], discovered with the 6-ft. Dollond, on June 8, 1772.

Caroline Herschel
May 22, 1783. Observed M11, M5 (which she first took for a comet), M10, and M12.

William Herschel
[PT 1818 p. 438, reprinted in Scientific Papers, Vol. 2, p. 596]
The 11th of the Connoissance. [M 11 = NGC 6705]
"1799, 10 feet finder. The cluster is visible; and, directed by neighboring stars, it may be seen by the eye."
"1783, 1799, 10 feet telescope. Power 300. With 3 inches aperture, the small stars are not to be distinguished; with 4 inch I can see them."
"1803, 1810, large 10 feet telescope. The cluster is of an irregular form, from 9 to 12 minutes in diameter."
The 10 feet telescope with an aperture of 4 inches, had a gauging power of 12.02; the profundity of this cluster is therefore of the 144th order. It is in the milky way.

John Herschel (1833): h 2019.
h 2019 = M11.
Sweep 82 (July 23, 1827)
RA 18h 42m 0.1s, NPD 96d 24' 42" (1830.0) [Right Ascension and North Polar Distance]
A beautiful irregularly R cl 10' or 12' diam. The stars are all 11m except one = 9m whose place is taken. Examined with high magnifiers [I have often viewed it with 800 and even 1200]; it is broken into 5 or 6 distinct groups with rifts or cracks between them.
A beautiful irregularly round cluster 10' or 12' in diameter. The stars are all of 11th magnitude except one which is of 9th magnitude, whose place is taken. Examined with high magnifiers [I have often viewed it with magnification 800 and even 1200]; it is broken into 5 or 6 distinct groups with rifts or cracks between them.

Sweep 85 (July 29, 1827)
RA 18h 42m 1.1s, NPD 96d 28' 27" (1830.0)
A glorious object. The bright * 9 m out of the centre taken.
A glorious object. The bright star of 9th magnitude out of the centre taken.

Smyth: DCLXIV [664]. M11.
DCLXIV. 11 M. Antinoi [now Scuti].
AR 18h 42m 32s, Dec S 6d 27'.2
Mean Epoch of Observation: 1835.57 [Jul 1835]
[with drawing]
A splendid cluster of stars, closely to the east-south-east of the above described object [a double star]; it precedes the left foot of Antinous, and is on the dexter chief of Sobieski's shield [Scutum]. This object, which somewhat resembles a flight of wild ducks in shape, is a gathering of minute stars, with a prominent 8th-magnitude in the middle, and two following; but by all analogy these are decidedly between us and the cluster. This, however, was not the opinion of Kirch, its discoverer, who, in 1681, described it as a small obscure spot, with a star shining through, and rendering it more luminous. Dr. Derham first resolved it into stars, with his 8-foot reflector, as shown in the Philosophical Transactions for 1733: "it is not," said he, "a nebulose, but a cluster of stars, somewhat like that which is in the Milky Way." That in the Milky Way!
Dr. Halley drew up a description of the nebular wonders, in 1716. They then amounted to six; but he says, "There are undoubtedly more which have not yet come to our knowledge." He could little foresee the rich harvest which was soon reaped; but his reasoning was very fair for the commencement. "Through all these spots," he observes, "are in appearance but little, and most of them but a few minutes in diameter; yet since they are among the fixt stars, that is, since they have no annual parallax, they cannot fail to occupy spaces immensely great, and perhaps not less than our whole solar system. In all theseso vast spaces it should seem that there is a perpetual uninterrupted day, which may furnish matter of speculation, as well to the curious naturalist as to the astronomer."
This fine object is on the shield by which Hevelius intended, FOR EVER, to honor John III., king of Poland. In the Prodomus Astronomiae, he appears to be uncommonly elated on having raised it to perpetual memory of the glorious liberator of Vienna - "ob immensa ejus merita, heroicas animi dotes, magnanimitatem, et ob res strenuè, ac fortiter gestas." He was delighted in being able to place it in the happiest part of the firmament, where all the members and neighbors are significant. "I wish to know, benevolant reader," he says, "that this shield consists of lucid stars, partly of the fourth magnitude; four of htese are placed in the border of this shield, and designate the princes of our serene king, who at that time were all among the living. In the middle of the shield I have designed a cross, in eternal remembrance of the battles most happily fought by him for the Christian faith: three notable stars shine in this cross, of which one indicates his own royal person, another the queen's, and a third the princess's, his only daughter; so that these seven stars represent the whole reighning family." This, and much more, shows his anxiety and hope of its eternal duration; but, poor fellow, Mr. Baily has taken the field, and Sobieski is one of the first among the asterisms recently doomed to proscription. I hope his pruning-knife is to be applied to many other interlopers, most of whom are far more pretty than this.

Lord Rosse

John Herschel, General Catalogue: GC 4437.
GC 4437 = h 2019 = M11.
RA 18h 43m 37.2s, NPD 96d 26' 7.6" (1860.0) [Right Ascension and North Polar Distance]
!; Cl; vB; L; iR; Ri; st 1 L, 11... . 8 observations by W. & J. Herschel.
Remarkable; cluster; very bright; large; irregularly round; rich; one large [bright] star and stars of 11th magnitude and fainter.
Remark: Figure in Lam. [Lamont's "Oefentliche Vorlesung über die Nebelflecken" - Public Lecture on the nebulous spots, Munich 1837], plate i, fig. 7.

[Further Observations on the Spectra of some Nebulae, with a Mode of determining the Brightness of these Bodies. Phil. Trans. Roy. Soc., Vol. 156 (1866), p. 381-397; here p. 390]
[No. [GC] 4437. 2019 h. 11 M. R.A. 18h 43m 37s.2. N.P.D. 96d 26' 7".6. Cluster; very bright.]
"Stars curiously broken up into groups." - Lord Oxmantown [Rosse]
The continuous spectra of all the brighter stars of this cluster were separately visible. When the clockwork of the equatoreal was stopped, an interesting spectacle was presented by the flashing in rapid succession of the linear spectra of the minute stars of the cluster as they pass before the slit.

In no part of the cluster was any trace of bright lines detected. (*)

(*) This absence of any indication of gaseous matter is in accordance with telescopic observation. D'Arrest remarks of this cluster, "Mit Verg. 11 zerfällt der Sternhauf in deutlich gesonderte gruppen mit leeren zwischenräumen. [With magn. 11 the star cluster breaks up in distinctly separated groups with empty spaces between them.]" - Beobach. der Nebelflecken und Sternhaufen, p. 346.

Dreyer: NGC 6705.
NGC 6705 = GC 4437 = h 2019; Kirch 1681, M 11.
RA 18h 43m 33s, NPD 96d 25.9' (1860.0) [Right Ascension and North Polar Distance]
!, Cl, vB, L, iR, Ri, *9, st 11...; = M11
Remarkable, cluster, very bright, large, irregularly round, rich, a star of 9th magnitude, stars of 11th magnitude and fainter.
Remark: Figures in Lam. [Lamont, Ueber die Nebelflecken, Munich 1837], plate I, fig. 7; Helmert [Publ. d. Hamburg. Sternw. i], plate I, II.

[Descriptions of 762 Nebulae ans Clusters photographed with the Crossley Reflector. Publ. Lick Obs., No. 13, Part I, p. 9-42]
NGC 6705, RA=18:45.7, Dec=- 6:23. M. 11. Bright, rather open cluster 6' in diameter; not globular. 0 s.n.
  • Observing Reports for M11 (IAAC Netastrocatalog)

    Hartmut Frommert
    Christine Kronberg

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    Last Modification: February 9, 2005