Messier 8

Cluster NGC 6530 discovered by Flamsteed about 1680. Lagoon Nebula discovered by Le Gentil in 1747.

Messier: M8.

May 23, 1764. 8. 17h 49m 58s (267d 29' 30") -24d 21' 10"
A cluster which appears like a nebula in an ordinary telescope of 3 feet [FL] but with an excellent instrument, one perceives nothing but a large number of small stars; near this star cluster is a fairly bright star, surrounded by a very faint glow: this is 9 Sagittarii, of 7th mag, according to Flamsteed: this cluster appears in elongated shape, extended NE-SW, between the arc of Sagittarius & the foot of Ophiuchus. (Diam. 30')

[Handwritten remark:] Lacaille has it.

[Mem. Acad. for 1771, p. 438-439 (first Messier catalog)]
I also have determined, in the same night [May 23 to 24, 1764], the position of a small star cluster which one sees in the form of a nebula, if one views it with an ordinary [non-achromatic] refractor of 3 feet [FL], but when employing a good instrument one notices a large quantity of small stars: near this cluster is a rather brilliant star which is surrounded by a very faint light: this is the nineth star of Sagittarius, of seventh magnitude, according to the catalog of Flamsteed: this cluster appears in an elongated shape which extends from North-East to South-West. I observed its position during its passage of the Meridian, comparing it with the star Delta Sagittarii, & I determined its right ascension as 267d 29' 30", & its declination as 24d 21' 10" south. This star cluster could have an extension, from North-East to South-West, of about 30 minutes of arc.
[p. 455] 1764.May.23. RA: 267.29.30, Dec: 24.21.10.A, Diam: 0.30. Cluster of stars between the bow of Sagittarius & the right foot of Ophiuchus; this cluster contains the star of 7th magnitude, 9 Sagittarii, according to the catalog of Flamsteed.

Flamsteed: No. 2446.

several times (H Coel Brit I, 33, 34; II, 48, 532, 533) around 1680: nebulosa antecedentem arcum (nebulosity preceding the arc [of Sagittarius])

De Chéseaux: De Ch. No. 8.

"Another one [cluster] in the bow of Sagittarius, observed by the same [Flamsteed; as the Double Cluster h+Chi Per]."

Le Gentil

[1749: Mémoire sur une Étoile Nébuleuse (Memoir of a Nebulous Star); presented December 3, 1749. Sav. Etr., Vol. II, p. 137-144, here p. 142-3]
The first [nebula] is between the left heel of Serpentarius [Ophiuchus] & the bow of Sagittarius, to the west of a star cluster which is located in this place in the sky, & which appears the same at eyesight, rather resembling the nebula of Cancer [Praesepe, M44]: That nebula has exactly the shape of an equilateral triangle, a bit elongated, & the turning point to the south-west. I have observed it with a refractor of 18 to 20 feet [FL], & it always appeared to me nebulous & transparent; it touches with its base a rather beautiful star, seen in the refractor, & which is the brightest of all those which compose the star cluster I have mentioned. The right ascension of this star is for the beginning of 1748, 266d 44' 22" [17h 46m 57s], its southern declination, 25d 8' 10", its [ecliptical] longitude, 26d 45' 00", & its southern [ecliptical] latitude 1d 30' 00".

[1759: Remarques sur les Étoile Nébuleuses (Remarks on the Nebulous Stars). Presented July 26, 1758. Mem. Acad., 1759, p. 453-471. Here p. 454]
First, the cluster of stars which is in the Milky Way near the bow of Sagittarius, near the ecliptic, & in which I discovered in 1747, a small nebulosity resembling the tail of a comet: this cluster of stars appeared to me very numerous; but I had sufficient difficulty to distinguish the nebulosity, because it appeared very dim; when on the contrary I used the refractors of twelve & of five feet [focal] length only, it appeared very similar to the more transparent & the more whitish places of the Milky Way.

Lacaille: Lac III.13.

17:48:41, -24:20:15
Three stars enclosed in a drag of a nebula parallel to the Equator.
[1763] Observed on April 6, 1752

Bode: Bode 44, Bode 45, Bode 49

Bode 44: Small stars close together in a nebula.
Bode 45: A nebula.
Bode 49: Three small stars with a nebula.

Koehler: Koehler No. 3

Not far from the preceding [M28], in 26deg [Sgr] [266d] and 0d 45' southern latitude, is a double star cluster, around which in the 3-foot Dollond [refractor] under clear air, a sort of pale glowing is noted.

William Herschel

[Unpublished Observations of Messier's Nebulae and Clusters. Scientific Papers, Vol. 2, p. 651-2]
1784 May 22 (Sw. 223). L. E. pB. broad. [Large, Extended (elongated), pretty bright, broad.] The nebulosity of the milky kind, there are some pB [pretty bright] stars in it, but they seem to have no connection w3ith it, being of very different sizes [magnitudes] and colours and resembling the other stars that are everywhere scattered about in this neighborhood. This is probably the star surrounded with nebulosity mentioned by Messier. There is indeed one of the stars which are in the nebula that is somewhat larger [brighter] than the rest and may be the only one he saw. The nebula follows 51 Ophiuchi 32'.4 in time and is 35' more south.

John Herschel (1847): h 3722.

h 3722 = M8.
Sweep 453 (May 13, 1834).
RA 17h 53m 25.1s, NPD 114d 21m 0s (1830.0) [Right Ascension and North Polar Distance]
A * 6 m (A c 2074) within the arch of the great nebula M8.
A star of 6th mgnitude (A c 2074) within the arch of the great nebula M8.

Sweep 474 (July 29, 1834).
RA 17h 53m 27.6s, NPD 114d 21m 4s (1830.0)
A noble nebula; to be monographed. The star taken is A c 2074 = 9 Sagittarii 7 m. It is followed by the great cluster VI.13 of which with the nebula fills many fields.
A noble nebula; to be monographed. The star taken is A c 2074 = 9 Sagittarii of 7th magnitude. It is followed by the great cluster of [William Herschel] class VI [Very compressed and rich star clusters].13 of which with the nebula fills many fields.

Sweep 793 (June 27, 1837).
RA 17h 53m 30.1s, NPD 114d 21m 13s (1830.0)
Superb nebula. The star A taken. See Pl. I. fig. 1.

"A collection of nebulous folds and matter surrounding and including a number of dark, oval vacancies and, in one place, coming to so great degree of brightness as to offer the appearance of an elongated nucleus. Superimposed upon this nebula and extending in one direction beyond its area, is a fine and rich cluster of scattered stars which seems to have no connection with it as the nebula does not, as in the region of Orion, show any tendency to congregate about the stars."

John Herschel, General Catalogue: GC 4361.

GC 4361 = h 3722 = M8.
RA 17h 55m 17.9s, NPD 114d 21m 15.3s (1860.0) [Right Ascension and North Polar Distance]
!!!; vB; eL; eiF; with L Cl 8 observations by W. & J. Herschel, "Mon."
Magnificient; very bright; extremely large; extremely irregular figure [shape]; with large cluster.
Remark: "Mon. (Monographing)": Frequently observed for the purpose of exact delineation.

GC 4366.
GC 4366 = h 3725.
RA 17h 56m 6.0s, NPD 114d 19m 58.9s (1860.0)
Cl; B; L; pRi; fL neb p. 2 observations by W. & J. Herschel.
Cluster, bright, large, pretty rich, following [east of] a large nebula [M8] which is preceding [west of] it.

Dreyer: NGC 6523.

NGC 6523 = GC 4361 = h 3722; Lac III.13, M 8.
RA 17h 55m 6s, NPD 114d 22.8m (1860.0) [Right Ascension and North Polar Distance]
!!! vB, eL, eiF, with L Cl; = M8
Magnificient, very bright, extremely large, extremely irregular figure [shape], with large cluster.
Remark: Figure in C.G.H. [JH 1847], plate I, fig. 1.

NGC 6530.
NGC 6530 = GC 4366 = h 3725.
RA 17h 56m 6s, NPD 114d 20.0m (1860.0)
Cl, B, L, pRi, f M8
Cluster, bright, large, pretty rich, following [east of] M8.

Curtis

[Descriptions of 762 Nebulae ans Clusters photographed with the Crossley Reflector. Publ. Lick Obs., No. 13, Part I, p. 9-42]
NGC 6523, RA=17:58, Dec=-24:23. [Publ. Lick Obs.] Vol. VIII, Plate 56. M. 8; the great diffuse nebulosity in Sagittarius; very bright, and of wonderfully intricate structure; covering an area of atleast 50'x36'. 0 s.n.