Messier 7

Known to Ptolemy 130 AD.

Messier: M7.

May 23, 1764. 7. 17h 38m 02s (264d 30' 24") -34d 40' 34"
A star cluster, more considerable than the preceding [M6]; to the naked eye, this cluster looks like a nebulosity; it is little distant from the preceding, placed between the bow of Sagittarius & the tail of Scorpius. (Diam. 30')

[Handwritten remark:] Lacaille has it.

[Mem. Acad. for 1771, p. 438 (first Messier catalog)]
I have determined in the same night [May 23 to 24, 1764] the position of another star cluster which is more considerable & of a larger extension: its diameter could occupy 30 arc minutes. This star cluster also appears at simple view [to the unaided eye] like a considerable nebulosity: but when examining it with a refractor, the nebulosity disappears, & one perceives nothing but a cluster of small stars, among which there is one which has more light: this cluster is little distant from the preceding; it is between the bow of Sagittarius & the tail of Scorpius. I observed in the Meridian the passage of the middle of this cluster, & compared it to the star Epsilon Sagittarii for determining its position: its right ascension was 264d 30' 24", & its declination 34d 40' 34" south.
[p. 455] 1764.May.23. RA: 264.30.24, Dec: 34.40.34.A, Diam: 0.30. Cluster of stars, little distant from the preceding, between the bow of Sagittarius & the tail of Scorpius.

Ptolemy (about 130 A.D.; Almagest): No. 567.

A nebulous cluster following the sting of Scorpius.

Ulegh Begh: Ulegh Begh 564.

Hodierna: Ha II.2.

Halley (1678): Halley No. 29.

[Catalog of Southern Stars] No. 29. Nebulous star at longitude 264:00, latitude -13:25:05 (1678), = RA 17:53.8, Dec -36:53:42 (2000.0)

Derham: No. 16 (2nd appended)

(1733) [Nebulosa (nebulous star)] Between Scorpio's Tail, and the Bow of Sagittarius, at 14d 32' 00" Scorpio Long. and 11d 25' 00" S. Lat.

De Chéseaux: De Ch. No. 10.

[Together with No. 9 = NGC 6231] "The two last [objects] of the catalog of Messieurs Derham and Maupertuis."

Lacaille: Lac II.14.

17:37:12, -34:39:55.
Group of 15 or 20 stars very close together, in the figure of a square.
[1763] Observed on June 15, 1752.

Bode: Bode 41

"A star cluster."

William Herschel

[Unpublished Observations of Messier's Nebulae and Clusters. Scientific Papers, Volume 2, p. 651]
1783, July 30. About 20 stars. [Only seen once.]

John Herschel (1847): h 3710.

h 3710 [ = M. 7]
Sweep 592 (May 29, 1835).
RA 17h 42m 39.6s, NPD 124d 46m 21s (1830.0) [Right Ascension and North Polar Distance]
A brill coarse cl VIII. class, of about 60 st 7.8....12 m, which fills field. Irreg. fig. A * 8 m taken.
A brilliant coarse cluster of the VIII. class [after William Herschel, a "Coarsely scattered clusters of stars"], of about 60 st 7.8....12 m, which fills the field. Irregular figure. A star of 8th magnitude taken.

Sweep 791 (June 7, 1837).
RA 17h 42m 39.6s, NPD 124d 45m 40s (1830.0)
cl VIII [Cluster of W. Herschel's class VIII]. Very fine and brilliant; stars of very large and mixed magnitudes. Fills field.

[JH wrongly assigns his h 3708 = NGC 6453, a globular cluster discovered by him, "= M. 7?"]

John Herschel, General Catalogue: GC 4340.

GC 4340 = h 3710 = M7 (Lacaille).
RA 17h 44m 39.6s, NPD 124d 46m 37.9s (1860.0) [Right Ascension and North Polar Distance]
Cl; vB; pRi; lC; st 7...12. 3 observations by W. & J. Herschel.
Cluster; very bright; pretty rich; little compressed; stars from 7th to 12th magnitude.

Dreyer: NGC 6475.

NGC 6475 = GC 4340 = h 3710; Halley, Lac II.14, M 7.
RA 17h 44m 40s, NPD 124d 46.5m (1860.0) [Right Ascension and North Polar Distance]
Cl, vB, pRi, lC, st 7...12; = M7
Cluster, very bright, pretty rich, little compressed, stars from 7th to 12th magnitude.
Remark: Figure in Blanchini [Observationes Selectae, Verona, 1737], p. 231.