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NGC 6366 (14,473 of 18,816)


oc gc pln bn dn gx gxcl ast aka lost




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NGC 6366

NGC 6366, C 1725-050, GCl 65, GC 4301

RA: 17h 27m 44.33s
Dec: −05° 04′ 35.9″

Con: Ophiuchus
Ch: MSA:1322, U2:248, SA:15


(reference key)

Type: globular cluster

Mag: B=?, V=9.5

Size: 13′
PA: ?

Published comments

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a 12.0 mag globular cluster.

Photo index

Photo Index by Jim Lucyk: Vehrenberg's Atlas of DS Splendors (3ed) p181.

Harris, W.E. (1997)

RA 17 27 44.3 (2000) Dec -05 04 36 Integrated V magnitude 9.20 Central surface brightness, V magnitudes per square arcsecond 21.24 Integrated spectral type - Central concentration, c = log(r_total/r_core); a 'c' denotes a core-collapsed cluster .92 Core radius in arcmin 1.83. ["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) ]

Helwan Obs. Bulletin No 21 (1920)

A loose cluster of vF stars some 15'x15'

Melotte, P.J. (1915)

A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.

Modern observations

Walter Scott Houston

This globular cluster lies a quarter of a degree east of 47 Ophiuchi, and Walter Scott Houston reports that it appears only 3' across in his 4" refractor, and about 5' across in the 20" Clark refractor at Van Vleck Observatory, Connecticut. The globular's concentration rating is 11/12, and Houston notes that in the 20-inch "it appears more like a highly compressed open cluster."

Tom Lorenzin

Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "12M; 4' diameter; fairly large, faint and unresolved with little brighter center; 11 and 12M stars to NW; 12 and 13M stars superimposed a few seconds N of core; 10' due E of 5M 47 OPH."

Steve Coe

Steve Coe, using a 13" f/5.6, notes: " Faint, large, round, not brighter in the middle at 135X. I counted 11 stars when I raised the power to 220X on this low surface brightness globular. It is somewhat strange for a globular in that it is not compressed at all. It looks like a pretty faint open cluster with several brighter members. When a friend looked into the eyepiece, he said it looked like oatmeal. I agreed."

Contemporary observations

Auke Slotegraaf

1995 June 01

1995-06-01: 11x80. Kelsey Farm. 22:00 SAST. East of 47 Oph. This globular looks very much like an internal reflection of the reasonably bright 47 Oph near. Needs averted vision to show it clearly as a vague hazy image.

1997 July 07

1997 July 7, Monday, 21:00 - 24:00 Jonkershoek. 11x80's tripod-mounted. Very faint cluster, with 47 Oph due west. A small star precedes the cluster, between cluster and star. Requires attention and a star chart to locate. Not casually seen. One of the faintest clusters Ive yet seen.

Tom Bryant

2007-09-12 21:45:00

Observing site: Pinnacles overlook

Telescope: C-8

[17h 27m 42s, -5 5' 0"] A faint, diffuse object at the southern end of a 4 star chain. Hard to see.

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