Messier 71

Discovered by Philippe Loys de Chéseaux in 1745-46.
Independently rediscovered by Johann Gottfried Koehler between 1772 and 1779.
Independently rediscovered by Pierre Méchain on June 28, 1780.

Messier: M71.

October 4, 1780. 71. 19h 43m 57s (295d 59' 06") +18d 13' 00"
Méchain: (296d 00' 04") +18d 14' 21"
"Nebula discovered by M. Méchain on June 28, 1780, between the stars Gamma and Delta Sagittae. On October 4 following, M. Messier looked for it: its light is very faint & it contains no star; the least light makes it disappear. It is situated about 4 degrees below [south of] that which M. Messier discovered in Vulpecula. See No. 27. He reported it on the Chart of the Comet of 1779." (diam 3.5')

De Chéseaux: De Ch. No. 13.

[with No. 12 = M35] "Two others of which I didn't yet determine the positions, one above the northern feet of Gemini, and the other above and very near to Sagitta."

Koehler: Koehler No. 7

"A very pale nebula in the Arrow [Sagitta] at 1deg 50' [Aqr] [301d 50'] and 39d northern latitude."

Caroline Herschel

July 23, 1783. Observed M71 togerther with M27 and M14; on that day, also discovered NGC 6866.

William Herschel

[PT 1818 p. 447, SP2 p. 600]
The 71st of the Connoissance. [M 71 = NGC 6838]
"1794, 7 feet telescope. With 120 and 160 the stars of it become just visible."
"1783, 1899, 1810, 10 feet telescope. A cluster of stars of an irregular figure."
"1784, 1799, 1807, 20 feet telescope. It is situated in the milky way, and the stars are probably in the extent of it; it is however considerably condensed; about 3 minutes in diameter."
"1805, large 10 feet telescope. An irregular cluster of very small stars, 2'35" in diameter."
By the observation with the 7 feet telescope, the profundity of this cluster is of the 243d order. It is in the following branch of the milky way.

John Herschel (1833): h 2056.

h 2056 = M71.
Sweep 360 (August 3, 1831)
RA 19h 46m 5.7s, NPD 71d 41' 14s (1830.0) [Right Ascension and North Polar Distance]
v rich; m comp; g b M; an irreg R cl of vS stars, inclining to triangular form. In a rich part of Milky Way.
Very rich; much compressed; gradually brighter toward the middle; an irregularly round cluster of very small [faint] stars, inclining to triangular form. In a rich part of Milky Way.

Sweep 90 (August 24, 1827
RA 19h 46m 8.0s, NPD 71d 38' 31s (1830.0)
v L; loose; fills field; a fine object; stars 11...16 m; the most condensed part = 3', of a triangular figure, the angle northward.
Very large; loose; fills field [of view]; a fine object; stars of 11th to 16th magnitude; the most condensed part is 3' in diameter, of a triangular figure, the angle northward.

Sweep 364 (August 8, 1831)
RA 19h 46m 12.1s, NPD 71d 38' 42s (1830.0)
An irreg R mass of closely packed st; g b M; 3' or 4' diam; a decided cl; but towards the s p the Milky Way is immensely rich.
An irregularly round mass of closely packed stars; gradually brighter toward the middle; 3' or 4' diameter; a decided cluster; but towards the south preceding [SW] the Milky Way is immensely rich.

Smyth: DCCXXV [725]. M71.

DCCXXV. 71 M. Sagittae.
AR 19h 46m 36s, Dec N 18d 22'.1
Mean Epoch of Observation: 1836.65 [Jul 1836]
A rich compressed Milky-Way cluster on the shaft of the arrow, and 10deg north-a quarter-east from Altair [Alpha Aquilae]. It was discovered by Mechain in 1781, and described by Messier asa nebula unaccompanied by stars, and of a very feeble light. Piazzi seems to have observed it meridionally as a star of the 8th magnitude, by admitting the light of a lamp upon it (312 P. xix), but his darkened field ought to have shown that it is flanked with four telescopic stars, besides other larger [brighter] companions in view. It was first resolved into stars by Sir William Herschel, in 1738, who esteemed its profundity to be of the 243rd order.

John Herschel, General Catalogue: GC 4520.

GC 4520 = h 2056 = M71.
RA 19h 47m 28.8s, NPD 71d 34' 55.1" (1860.0) [Right Ascension and North Polar Distance]
Cl; vL; vRi, pmC, st 11...16. 13 observations by W. & J. Herschel.
Cluster; very large; very rich; pretty much compressed; stars from 11th to 14th magnitude.

Dreyer: NGC 6838.

NGC 6838 = GC 4520 = h 2056; Méchain, M 71.
RA 19h 47m 30s, NPD 71d 35.1' (1860.0) [Right Ascension and North Polar Distance]
Cl, vL, vRi, pmC, st 11...16; = M71
Cluster, very large, very rich, pretty much compressed, stars from 11th to 14th magnitude.

Curtis

[Descriptions of 762 Nebulae and Clusters photographed with the Crossley Reflector. Publ. Lick Obs., No. 13, Part I, p. 9-42]
NGC 6838, RA=19:49.3, Dec=18:31. Rather sparse globular cluster 5' in diameter. 0 s.n.