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RA: 17h 50m 51.77s
Dec: −34° 35′ 55.1″
Ch: MSA:1437, U2:377, SA:22
Ref: SIMBAD, SEDS
Type: globular cluster
Mag: B=10.49, V=10.08
Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "a highly condensed nebulous mass, 3' diam, or an irreg R neb; pmbM, resolvable."
"Considerably large, irregular shape, pretty much brighter towards the middle, mottled appearance."
pF, S, irreg. R., almost certainly a globlar cluster in a very rich field of stars.
(Sulentic and Tifft 1973) notes that this is a 11.5 mag globular cluster.
RA 17 50 51.8 (2000) Dec -34 35 55 Integrated V magnitude 10.08 Central surface brightness, V magnitudes per square arcsecond 17.35 Integrated spectral type F8 Central concentration, c = log(r_total/r_core); a 'c' denotes a core-collapsed cluster 2.50c: Core radius in arcmin .07. ["Catalog Of Parameters For Milky Way Globular Clusters", compiled by William E. Harris, McMaster University. (Revised: May 15, 1997; from http://www.physics.mcmaster.ca/Globular.html; Harris, W.E. 1996, AJ, 112, 1487) ]
Harrington, P. (1986) An observer's guide to globular clusters. Sky&Telescope, Aug, 198.
A careful scan of the area with a telescope will reveal NGC 6453 just one-third degree northwerst of the second bvrightest star in M7. IT was first seen by h in 1837. Only 3.5 min in diameter and 10th mag this cluster will be a challendge for observers using small telescoipes.
Steve Coe, observing with a 17.5" f/4.5 at 100X, notes: "Pretty faint, pretty small, round, somewhat brighter in the middle at 135X. Two stars are resolved at 320X.
10x50 tripod-mounted. 1997-07-06. Nothing visible [Rui Henriques]
Observing with a 6-inch f/8.6 Newtonian at 52x, it appears as a faint nebulous presence west of M7. It has a 9m star east and a 10m star closer west. It does not magnify well in the 6-inch; 52x shows it with attention, 108x larger but not clearer, and 325x is too much. No further details seen.
Observing site: Pinnacles overlook
[17h 50m 54s, -34° 36' 0"] A very small, faint patch.
The Messier objects
The Bennett objects
The Caldwell list
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