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RA: 18h 55m 3.28s
Dec: −30° 28′ 42.6″
Ch: MSA:1412, U2:378, SA:22
Ref: SIMBAD, SEDS
Type: globular cluster
Mag: B=9.2, V=8.37
Discovered by Messier in July 1778, he called this globular a " very bright nebula, discovered in Sagittarius.. It is bright in the centre and contains no star, seen with an achromatic telescope of 3.5 feet".
In the Appendix to the 1912 'Scientific Papers of Sir William Herschel' this object is described as "1784, June 24. A round, resolvable nebula. Very bright in the middle and the brightness diminishing gradually, about 2.5' or 3' diameter. 240 power shews two pretty large stars in the faint part of the nebulosity, but I rather suppose them to have no connection with the nebula. I believe it to be no other than a miniature cluster of very compressed stars resembling that near the 42nd Comae [M53]. It is like that under Delta Sagittarii [I.50 = NGC 6624], but rather larger and brighter tho' not much. 1784, July 13. A cL, vB, R, nebula, mbM, and breaking off suddenly, the rest being much fainter."
James Dunlop observed this object from Paramatta, New South Wales, and included it as No. 624 in his catalogue of 1827. Using a 9-inch f/12 telescope, he described it as "a very beautiful nebula, with a very bright round well-defined disk or nuclei, about 15 arcseconds diameter, surrounded by a gradually decreasing light or chevelure, about 1 1/4' diameter, this is exceedingly bright immediately at the centre."
Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "globular, B, R, gmbM, diam in RA = 9 seconds, clearly resolved with left eye." On a second occassion he called it "globular, B, pL, vlE, gbM, 2.5' diameter, resolved into stars 15m, with a few outliers 14m." His third observation was recorded as "vvB, R, psvmbM, to a large nipple, diam 2.5', pos of a star 13m almost involved = approx 147 degrees." On July 16, 1836 he wrote: "Observing in equatorial [5-inch refractor] zone review; B, sbM, 90 arcseconds."
The NGC records "at first gradually, then suddenly much brighter in the middle, well-resolved, clearly seen to consist of stars which are chiefly 15th magnitude with a few outliers of 14 mag. 2.5' diameter."
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
RA 18 55 03.3 (2000) Dec -30 28 42 Integrated V magnitude 7.60 Central surface brightness, V magnitudes per square arcsecond 14.82 Integrated spectral type F7/8 Central concentration, c = log(r_total/r_core); a 'c' denotes a core-collapsed cluster 1.84 Core radius in arcmin .11. ["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) ]
Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part III. Southern Objects. M.N.R.A.S., 36(3), 91.
Burnham notes that "M54 seems perfectly round, showing no evident ellipticity, and has a rather high surface brightness which permits fairly high magnification. Although quite bright and strongly compressed, this is not as easy cluster to resolve; under good conditions it may show some sign of granularity with a 10- to 12-inch aperture; smaller telescopes show only a round fuzzy spot."
"globular cluster, extremely condensed"
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
The RNGC (Sulentic and Tifft 1973) notes that this is a 8.5 mag globular cluster.
Houston notes that this cluste is about 8th mag and has a 2.7' diameter in his 4-inch refractor. He reports that KG Jones writes: "looks almost like a planetary nebula at first sight".
Hartung notes that a 12-inch shows granularity but no real resolution.
Stewart Moore (Fleet, Hampshire, UK), observing with a 12-inch f/5, writes in the The Webb Society Nebulae and Clusters Section Report No. 10, July 1992: "Very bright and small, with a diameter of about 4'. Stands magnification well. Stars only resolved at edge of cluster. Perfectly round."
Tom Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "9M; 6' diameter; barely resolved round glow with very bright core; compressed and dense; 13M star SE of core."
Steve Coe, observing with a 13" f/5.6, notes: "(M 54) Bright, pretty large, round, much, much brighter in the middle at 165X. Resolved 5 stars at 220X. It could be seen in the 11X80 finder."
Location: Night Sky Caravan Farm, Bonnievale.
Date: 2016 Oct 30, Sunday.
Time: 22:29 SAST
Telescope: Little Martin (4-inch f/6.5 Celestron refractor)
11mm Nagler Type6 (60x): Tiny, furiously bright globular cluster, quite like a star with a halo.
30/04/93: Observing with a 6-inch f/8.6 Newtonian at 52x, the one-degree field is free of bright stars. The cluster is bright, and has a small bright nucleus.
1997 July 9, Wednesday, 20:00 - 22:00 Jonkershoek. 11x80's tripod-mounted. Moderate conditions. Small bright 8th mag glow, softly focussed star, but the distinguishing envelope readily 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
Moderately bright, medium in size, round compressed globular cluster, with a core becomes gradually brighter. Resolved stars, with a defuse envelope. Busy starfield.
12-inch f/10 SCT (EP: 2-inch 32mm SW 95x 42' fov; 2-inch 14mm UW 218x 23' fov)
Moderately bright, medium in size, round compressed globular cluster, with an outstanding strong core that gradually becomes much brighter. Resolved very faint stars with a defuse envelope (218x). A good example of an average globular in all its facets. Soft and hazy with a relatively wide centre that slowly brightens with a thin 1/5th soft peripheral halo. Busy star-field. Is M54 (NGC 6715 or Bennett 118) some of the remaining parts of the centre of our galaxy.
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 irregular frozen small tennis ball at 75x and that the stars in this cluster are well resolved.In overall I have found that M54 is a moderately condensed cluster where I have found that the stars in this cluster is arranged in a very tight halo towards the nucleus.The nucleus of this globular cluster is strongly concentrated where a large group of stars are seen radiating away from this cluster.This globular cluster measures 2.7'x 2.8'.Chart No.327,NSOG Vol2.
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 globular cluster.
Chart Number:No.18(Extract taken out of "Atlas of the Night Sky").
Size:26mm Eyepiece:Field Of View:57'/15=3.8'.
20mm Eyepiece:Field Of View:50'/13=3.8'.
Size in Arc Minutes:3.8'(Nucleus).
Globular Cluster is 3.8'*1.2'.
Brightness Profile:Straight from the central outskirts of this globular cluster it is bright all over.
Challenge Rating:Very Easy.
In this globular cluster all the stars are partially resolved while on the central outskirts there is a granular appearance of bright stars.Most of the stars in this cluster are compact like a neat mottled snowflake.The stars are concentrated like a tight swarm of old stars while towards the outskirts of this cluster there is a large chain of bright stars.
The Messier objects
The Bennett objects
The Caldwell list
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