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RA: 18h 53m 4.32s
Dec: −08° 42′ 21.5″
Ch: MSA:1318, U2:295, SA:16
Ref: SIMBAD, SEDS
Type: globular cluster
Mag: B=9.85, V=8.69
Synonyms: H I-047
Discovered in 1784 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "B vL irregular figure, easily resolvable, stars visible."
Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "globular, pL, F, R, rather irreg, vglbM, 6' or more in diam, all resolved. A fine object, the stars bring very close and numerous."
Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part IV. M.N.R.A.S., 36(2), 58.
A study by W. W. Morgan of Yerkes Observatory indicates this globular cluster to have a spectral type of G0-G2.
Included in a list of doubtful objects;. A little, irregular knot of stars in a rich cloud.
The RNGC (Sulentic and Tifft 1973) notes that this is a 10.0 mag globular cluster.
Photo Index by Jim Lucyk: Burnhams V3 p1758, Deep Sky #23 Su88 p27.
RA 18 53 04.3 (2000) Dec -08 42 22 Integrated V magnitude 8.10 Central surface brightness, V magnitudes per square arcsecond 18.65 Integrated spectral type F9- Central concentration, c = log(r_total/r_core); a 'c' denotes a core-collapsed cluster .90 Core radius in arcmin .94. ["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) ]
"cluster, globular? somewhat irregular, fairly condensed"
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
Houston calls it a "tight ball of stars about 3' in diameter with a total magnitude of 9.0. Because of the rich background it is best to view NGC 6712 with high magnification. It was a difficult object with the 5-inch apogee scope at 20x, but years ago in Kansas it was easily seen with my old 10-inch reflector at 160x."
In Revue des Constellations, Sagot and Texereau describe it as "Hazy patch easily visible with a 2-inch refractor at 20x. Small and moderately difficult (from Paris), center very bright with 3.8-inch at 45x. Pretty cluster where a few stars are resolved in a 12.5-inch at 80x."
John Bortle (Webb Society Quarterly Journal, January 1976) using 10x50 binoculars, estimates the visual magnitude as 8.8.
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "9M; 3' diameter; formless glow with brighter center; just barely resolved at 200x; 14M stars over diffuse background glow; if you're feeling really lucky, try planetary I.1295 (14M; 1.5' diameter) 20' E and a little S; use low-x and N-filter."
Observer: Dave Mitsky (e-mail: email@example.com)
Instrument: 17-inch other Location: Harrisburg, Pa, U.S.A.
Light pollution: moderate Transparency: fair Seeing: fair
Time: Fri Jun 27 04:30:00 1997 UT Obs. no.: 155
I reobserved NGC 6712, a globular cluster in a rich area of the Milky Way near the planetary nebula IC 1295, because of the recent interest in this object on sci.astro.amateur. I first used a Cave 12.5" f/6.5 Newtonian reflector and at 65x (32mm U.O. Konig-II) the NGC 6712 appeared as a nebulous patch. Using my 19mm Panoptic (109x) did not resolve the globular. At 159x (13mm T.V. Ploessl) the cluster was somewhat resolved and had an irregular oval shape. About 45 minutes later I used a 17" f/15 classical Cassegrain at 202x (32mm Koing-II) and 341x (19 mm Panoptic) to view NGC 6712. At 341x I could see a distinctly elliptical shape and a hint of the dark lane on the southeast edge that the Webb Society's book on globular clusters mentions. NGC 6712 is a fairly large class 9 Herschel 400 globular of around 9th magnitude. I also located 2 new Herschel globulars that night, namely NGC 6144 near Antares and NGC 6426 northwest of Gamma Ophiuchi. NGC 6426 was particularly faint, being just at the limit of visibility with averted vision.
Steve Coe, observing with a 17.5" f/4.5 at 100X, notes: "Bright, little elongated, very rich, very compressed. Resolved at 100X, going to 165X brings out a myriad of dimmer members at the edge of resolution. This globular resides in a beautiful, rich Milky Way field that provides a lovely backround (foreground?).
Sandage & Smith (1966 ApJ 144,886): brtst *s V=13.3.
POSS: HD 174918 is 4'.3 NE, implies 1990 15cm diam of 3'.2. m13 * (V=13.33/
0.33, fld *) has m~14 comp ~5" SE (not meas by Sandage or Cudworth
due to crowding); m13 * lies 35" SE from center.
7cm - mod br @ 30x in v*ry fld. 50x: gran only but mostly nrby fld *s give
impression of part-res. BS, 26Apr1993, Anderson Mesa.
- mod br @ 30x, m10 * ENE, cl unres. 75x: gran, mod broad concen, clumpy
texture. a few *s clearly res on periphery. BS, 23Jun1996, Mars Hill.
8cm - easy. BS, 17Aug1982, Anderson Mesa.
15cm - not too br but neb haze stands out from sharp *ry bkgrnd. 3' diam, but
res @ 203x. BS, 28Mar1971, FtL.
- mod br gc in *ry fld, gran @ 80x. 140x: mod broad concen; oval, flattened
in halo on SW side. to NE cl reaches three-eighths way to m9 * ~4' away.
m13 * (pair) brtst on E edge of ill-def core. res only marginal @ 140x,
but a few doz *s @ 195x, prob best for this object. BS, 21Jun1990,
20cm - shows fairly br haze w/oval outline against *ry fld. 250x: partially res,
2'.5x2'. a br * nrby. JM/BS, 30Jul1971, FtL.
25cm - vlg and unres (perhaps optics). br bar of * N-S through center w/m11 * at
S end. outline is irreg round. 5' diam w/outliers. BS, FtL.
- only 2'.5 diam, f fld *s give impression of lgr size. gran to partially
res in 3" seeing. BS, 15Mar1981, Anderson Mesa.
30cm - nice. core 2'.5, outliers to 5'.5. S side flattened. well res. CBL, Roof.
60cm - def of gran: hundreds of *s just at threshold, too densely packed to show
good res, but distinct nonetheless. eight or ten brtr * overcast. vbroad
concen. much fewer outliers on W side, core unconcen. neat @ 250x. CBL?,
This globular cluster lies in a rich starfield of large and small stars. The cluster is a soft, even downy glow of light, very soothing and, somehow, "innocent." It is quite prominent and appears mottled.
1995 May 26, 03:00. 11x80 binoculars. Using averted vision, the cluster appears as a nebulous glow next to a 9th mag star.
1995-06-01: 11x80. Kelsey Farm. 23:00 SAST. In a rich diverse field, this little cluster is quite easy and has some close stellar companions. I must say, overall, it appears quite lost in this busy field.
1997 July 6, Sunday, 21:00 - 23:00 Jonkershoek. 11x80's tripod-mounted. Not at all separated from the background field, which is immensely rich. This cluster can be quite easily missed while sweeping.
1997 July 8, Tuesday, 20:55 - 23:30 Jonkershoek. 11x80's tripod-mounted. Small globular cluster, a 9th mag blur in a rich field. Reasonably difficult, but easy once seen.
Location: Campsite (South 23 16 East 29 26).
Sky conditions: Clear, steadiness good.
Instrument: Meade 8 inch, Super wide-angle, 18mm eyepiece; 36.2' fov
DSO Report N
Medium in size, faint irregular to round cotton ball getting a little brighter to the middle with faint stars in the fringy hazy edges. About 3 to 4 arc minutes.
12-inch f/10 SCT (EP: 2-inch 32mm SW 95x 42' fov; 2-inch 14mm UW 218x 23' fov; 2-inch 8.8mm UW 346x 15' fov)
This globular displays a faint irregular to round cotton ball getting a little brighter to a broad core. Faint stars peeking out of the glow in the east fringy hazy edge together with dark lanes that becomes visible with averted vision. To the south a few brighter stars are grouped together and the planetary nebula IC 1295 can be seen 20' arc minutes to the southeast of this globular.
Sky Conditions:The fainter parts of the Milky Way are barely visible.Haziness only visible on the horizon.Atmosphere stable with little interference.
This globular cluster has the shape of an out of focus frozen winter snowball and that the stars in this cluster has a granular appearance.The stars in NGC 6712 is strongly condensed as a soft halo of white light that grows brighter in the center compared to the outskirts of this cluster.This globular cluster is a small uniform compact cluster where the nucleus of this cluster is moderately condensed.This globular cluster measures 5.1'x 3.9'.Chart No.358,NSOG Vol.2.
Instrument:12-inch Dobsonian Reflector Telescope.
Sky Conditions:The fainter parts of the Milky Way are barely visible.
Transparency of the Sky:Haziness only visible on the horizon.
Seeing:Atmosphere stable with little interference.
Object Type:Globular Cluster.
First Impression:This object looks like a faint patch of light.
Chart Number:N0.187(Extract taken out of "Atlas of the Southern Night Sky").
Size:26mm Eyepiece:Field Of View:57'/13=4.3'.
20mm Eyepiece:Field Of View:50'/11.5=4.3'.
Size in Arc Minutes:4.3'(Nucleus).
Globular Cluster is 4.3'*1.4'.
Brightness Profile:The central nucleus of this globular cluster grows brighter compared to the far outskirts of this cluster.
All the stars in this globular cluster are partially resolved.Most of the stars are centrally concentrated towards each other.This globular cluster is seen as a fairly uniform halo of bright stars.Around the outskirts some of the stars are resolved but otherwise it looks somewhat like a patch of light where condensation is strong.
The Messier objects
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