Messier 56

Historical observations

William Herschel (c.1784)

In the Philosophical Transactions, 1814, William Herschel wrote "January 5, 1807. 20 feet telescope. Magnifying power 157.3. The 56th of the Connoissance des Temps is a globular cluster of very compressed and very small stars. They are gradually more compressed towards the centre." In the Philosophical Transactions, 1818, William Herschel wrote: "1783, 7 feet telescope. A strong suspicion of its being stars. 1783, 1799, 10 feet telescope. 120 power will not resolve it; 240 power wants light; 350 power however shows the stars, but they are so exceedingly close and small that they cannot be counted. 1784, 1807, 20 feet telescope. A globular cluster of very compressed small stars about 4 or 5' diameter. 1805, 1807, large 10 feet telescope. With 171 power it is 3' 36 seconds diameter."

Published comments

Sulentic & Tifft (1973)

(Sulentic and Tifft 1973) notes that this is a 9.5 mag globular cluster.

Doig, P. (1925)

Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part II. M.N.R.A.S., 35(8), 280.

Bailey, S.I. (1908)

"globular cluster? somewhat irregular, fairly condensed"

Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.

Harris, W.E. (1997)

RA 19 16 35.5 (2000) Dec +30 11 05 Integrated V magnitude 8.27 Central surface brightness, V magnitudes per square arcsecond 18.06 Integrated spectral type F5- Central concentration, c = log(r_total/r_core); a 'c' denotes a core-collapsed cluster 1.37 Core radius in arcmin .37. ["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) ]

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

MacRobert, Alan M

writes: "I can see something slightly unstarlike here in a finderscope, and on turning to the 6-inch's eyepiece, sure enough, there's a fine fuzzy glow embedded in a rich Milky Way starfield. A 10th mag star is off the cluster's western edge. At 200x it shows tantalizing signs of breaking up into innumerable faint stars, like a sugar pill in dim moonlight. It has a three-dimensional look to me at 200x that's not apparent at 45x."

Bushnall, Darren (1993)

Bushnall (Hartlepool, Cleveland) observing with a 8.5-inch f/6, writes in the The Webb Society Nebulae and Clusters Section Report No. 11, January 1993: "At low power, visible as a small smudge of light in a rich starfield. Some individual stars seen at x90 and the object is very granular. Diameter almost 2'. Mag 10 star on south-west side and mag 11.5 star a similar distance west."

Harrington, Phil (1986)

Harrington, P. (1986) An observer's guide to globular clusters. Sky&Telescope, Aug, 198.

.. shows as a round nebulous 8th mag glow in binocs and finderscopes. A few indiv stars are visible with 6inch and a 12inch will resolve the core.

Bortle, John (1976)

Bortle (Webb Society Quarterly Journal, January 1976) using 10x50 binoculars, estimates the visual magnitude as 8.5.

Hogsten, Scott (IAAC)

Observer: Scott Hogsten

Your skills: Intermediate (some years)

Date/time of observation: 7/28/98 - 10:40

Location of site: Perkins Obs. Delaware Ohio (Lat , Elev )

Site classification: Suburban

Sky darkness: 5 1-10 Scale (10 best)

Seeing: 6 1-10 Seeing Scale (10 best)

Moon presence: Minor - crescent or far from object

Instrument: 12.5" f5 Dob

Magnification: 90x 150x

Filter(s): None

Object(s): M56 / NGC 6779

Category: Globular cluster.

Constellation: LYR

Data: mag 8.3 size 7.1'

Position: RA 19:16.6 DEC +30:11

Description:

A pretty bright but small dense globular cluster. At 90x there was

just a hint of the stars beginning to be resolved at 150x some of

the outer stars of the cluster could be resolved but the core

could not be.

--

Tom Lorenzin

Lorenzin, in the e-version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "8M; 5' diameter; just barely resolved at 200x with 13M and dimmer members; much like N6760 but much larger and more easily resolved; on a line, and 40% of the distance between Beta CYG and Gamma LYR; ruddy, bright star 25' to NW is 6M SAO 68040, a type-M2 red giant."

Gramer, Lew (IAAC)

Observer: Lew Gramer; Your skills: Intermediate; Date and UT of Observation: 1997-07-4/5, 03:35 UT; Location: Savoy, MA, USA (42N, elev 700m); Site classification: rural; Limiting magnitude: 7.1 (zenith); Seeing: 5 of 10 - mediocre, increasing cumulus; Moon up: no; Instrument: 50mm Simmons binoculars; Magnification: 7x; Filters used: None; Object: M56; Category: Globular cluster; Constellation: Lyr; Data: mag 8.4 size 7'; RA/DE: 19h17m +30o11m;

Description: Roughly pointed to by, and just 1.5 binoc fields SW of, the bright base stars of Lyra (beta and gamma), M56 was a tiny, surprisingly bright dot of light in 7x50s, with just a hint of surrounding haze and no other features.

Contemporary observations

Richard Ford

2010 August 7, Saturday

Location:Kambro Padstal,Britstown.

Instrument:12"Dobsonian Reflector Telescope.

Sky Conditions:Dark moon and stars magnitude 6 and fainter are barely visible with the naked eye.

Transparency of the Sky:The most clear sky possible.

Seeing:Excellent clean sky,limited star flickering and brilliant objects.

Limiting Magnitude:6.5.

First Impression:Globular Cluster.

Location:Lyra.

Time:9:50pm.

Chart Number:No.6(Extract taken out of "Atlas of the Night Sky").

Size:26mm Eyepiece:Field of View:57'/10=5.7'.

20mm Eyepiece:Field of View:50'/9=5.5'.

5.7'+5.5'=11.2'.

11.2'/2=5.6'.

Size in Arc Minutes:5.6'.

Size of nucleus vs.halo:10/5.6'=1.7'.

9/5.6'=1.6'.

1.7'+1.6'=3.3'.

3.3'/2=1.6'.

Size of halo:1.6'.

Ratio:1:3.

Major Axis:5.6'.

5.6'/3=1.8'.

Minor Axis:1.8'.

Globular Cluster is 5.6*1.8'.

Brightness:Bright.

Brightness Profile:Medium Surface Brightness.

Challenge Rating:A spectacular sight to observe in a large telescope under a very dark sky.

Description

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All the individual stars in this globular cluster are partially resolved while the stars in this cluster are uniformly concentrated towards each other.It looks almost like a mottled snowball in appearance when observed. No chains of stars have been observed in this cluster. I have found no starless patches.