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[M 70]

Messier 70

Observations and Descriptions

Discovered on August 31, 1780 by Charles Messier.

Messier: M70.
August 31, 1780. 70. 18h 28m 53s (277d 13' 16") -32d 31' 07"
`Nebula without star, near the preceding [M69], & on the same parallel: near it is a star of the nineth magnitude & four small telescopic stars, almost on the same straight line, very close to one another, & [they] are situated above the nebula, as seen in a reversing telescope; the [position of the] nebula was determined from the same star Epsilon Sagittarii.' (diam 2')

[discovery announce in appendix of the Connoissance des Temps for 1783, p. 408]
`On August 31, 1780, M. Messier has once again discovered two nebulae placed below the left arm & near the arc of Sagittarius, both on the same parallel; here are their positions,
274d 11' 46" in right ascension & 32d 31' 45" in southern declination [M69]
277. 13. 16. .................... 32. 31. 7. [M70]

William Herschel
[Unpublished Observations of Messier's Nebulae and Clusters. Scientific Papers, Vol. 2, p. 658]
1784, July 13 (Sw. 237). er. cB. pL. iR. [extremely rich, considerably bright, pretty large, irregularly round]. A very faint red perceivable.

Dunlop: Dun 614.
No. 614. A.R. 18:33:24, S.P.D. 57:34 (1827) [Right Ascension and South Polar Distance]
"A pretty bright round nebula, about 1 1/2' diameter, very much condensed to the center." 5 Observations.

John Herschel (1847): h 3756.
h 3756 = M. 70 = Dun 614.
Sweep 477 (August 1, 1834)
RA 18h 32m 5.7s, NPD 122d 26' 46" (1830.0) [Right Ascension and North Polar Distance]
Glob. Cl.; B; R; g m b M; diam in RA = 7.0s; resolved into st 14...17 m.
Globular Cluster; bright; round; gradually much brighter toward the middle; diameter in RA = 7.0s [1.75']; resolved into stars of 14 to 17 m.

Sweep 478 (August 3, 1834)
RA 18h 32m 8.3s, NPD 122d 26' 35" (1830.0)

Glob. Cl.; B; R; g b M; resolved into st 15 m.
Globular Cluster; bright; round; gradually brighter toward the middle; resolved into stars of 15 m.

Sweep 619 (August 15, 1835)
RA 18h 32m 8.8s, NPD 122d 26' 54" (1830.0)
Seen and taken place, no description. [N.B. - This is no doubt M 70, though the PD of that object is stated at 121deg, which (all the above observations agreeing) must be the wrong degree.

John Herschel, General Catalogue: GC 4428.
GC 4428 = h 3756 = M70 = Dun 614.
RA 18h 34m 4.9s, NPD 122d 25' 12.6" (1860.0) [Right Ascension and North Polar Distance]
Glob. Cl., B, pL, R, gbM, st 14...17. 4 observations by W. & J. Herschel.
Globular Cluster; bright; pretty large; round; gradually brighter toward the middle; stars from 14th to 17th magnitude.
Remark: See the note on M69. [Piazzi, in note on xviii.122 of his catalogue, says that both M69 and M70 are 1deg more to the south. But he is wrong.]

Dreyer: NGC 6681.
NGC 6681 = GC 4428 = h 3756; M 70, Dunlop 614.
RA 18h 34m 5s, NPD 122d 25.2' (1860.0) [Right Ascension and North Polar Distance]
Glob. Cl., B, pL, R, gbM, st 14...17; = M70
Globular cluster, bright, pretty large, round, gradually brighter toward the middle, stars from 14th to 17th magnitude.
Remark: 6681. M70. See note on 6637 [M69]. [Piazzi, in note on XVIII.122 of his catalogue, says that both M69 and M70 are 1deg more to the south. But he is wrong. - JH]

Curtis
[Descriptions of 762 Nebulae and Clusters photographed with the Crossley Reflector. Publ. Lick Obs., No. 13, Part I, p. 9-42]
NGC 6681, RA=18:36.7, Dec=-32:23. M. 70. Bright condensed cluster 2' in diameter; doubtless globular. 0 s.n.
  • Observing Reports for M70 (IAAC Netastrocatalog)


    Hartmut Frommert
    Christine Kronberg
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    Last Modification: March 30, 2005