Known to Ptolemy 130 AD.
[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.
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?"]
Last Modification: August 11, 2023