Objects - Globular Clusters

Obects & Observing Tips:

Globular Clusters

Hercules Cluster M13

You are here: Haggart Observatory >> Favorite Objects >> Globular clusters

Globular Clusters
contain hundreds of thousands to about a million stars. They are made up of the most ancient stars known (older than the Milky Way galaxy). About 150 of them are known in our galaxy, scattered in a "halo" above and below the galaxy. Globular clusters have also been observed around other galaxies.

Observing Globular Clusters:

naked-eye: not visible
binoculars: the Hercules Cluster and a few others are visible as dim fuzzy spots in the sky - a "star" that won't come into focus
telescopes: very cool-looking balls of stars; try wide-field eyepieces (32mm, 40mm, 55mm in the 24"); no filter needed

Best Bets:
The Hercules Cluster (M13) looks so good (and is so easy to find) that we rarely show any others when it is available, even though there are many more. 29 of the Messier Objects are Globular Clusters. (Links are to data and descriptions at the SEDS website.) M79 isn't a great globular, but it's the only one around in winter.

Cluster	Constellation	Availability by month												Mag.	Dist. (ly)	Diam. (ly)	# Stars	Age (bil y)
Cluster	Constellation	J	F	M	A	M	J	J	A	S	O	N	D	Mag.	Dist. (ly)	Diam. (ly)	# Stars	Age (bil y)
M13	Hercules	-	-	-	-	X	X	X	X	X	X	-	-	5.9	25,100	145	1,000,000	14-24
M15	Pegasus	X	-	-	-	-	-	X	X	X	X	X	X	6.2	33,600	175	?	?
M22	Sagittarius	-	-	-	-	-	-	X	X	X	-	-	-	5.1	10,400	97	500,000	?
M79	Lepus	X	X	X	-	-	-	-	-	-	-	-	X	7.7	42,100	118	?	?

More globulars to try out: M3 and M5 are highly recommended by several sources.

Cluster	Constellation	Availability by month												Mag.	Dist. (ly)	Diam. (ly)	# Stars	Age (bil y)
Cluster	Constellation	J	F	M	A	M	J	J	A	S	O	N	D	Mag.	Dist. (ly)	Diam. (ly)	# Stars	Age (bil y)
M2	Aquarius	-	-	-	-	-	-	-	X	X	X	X	-	6.5	37,500	175	150,000	13
M3	Canes Venatici	-	X	X	X	X	X	X	X	-	-	-	-	6.4	33,900	214	500,000	5-26
M4	Scorpius	-	-	-	-	-	X	X	X	-	-	-	-	5.6	7,200	47	?	13
M5	Serpens (caput)	-	-	-	-	X	X	X	X	X	-	-	-	5.6	24,500	151	500,000	13
M9	Ophiuchus	-	-	-	-	-	X	X	X	X	-	-	-	7.7	25,800	65	?	?
M10	Ophiuchus	-	-	-	-	-	X	X	X	X	-	-	-	6.6	14,300	83	?	?
M12	Ophiuchus	-	-	-	-	-	X	X	X	X	-	-	-	6.7	16,000	75	?	?
M14	Ophiuchus	-	-	-	-	-	X	X	X	X	-	-	-	7.6	30,300	100	?	?
M19	Ophiuchus	-	-	-	-	-	X	X	X	X	-	-	-	6.8	28,000	110	?	?
M28	Sagittarius	-	-	-	-	-	-	X	X	X	-	-	-	6.8	18,300	60	?	?
M30	Capricorn	-	-	-	-	-	-	X	X	X	X	-	-	7.2	26,100	90	?	?
M53	Coma Berenices	-	-	X	X	X	X	X	-	-	-	-	-	7.6	58,000	220	?	?
M54	Sagittarius	-	-	-	-	-	-	X	X	X	-	-	-	7.6	87,400	300	?	?
M55	Sagittarius	-	-	-	-	-	-	X	X	X	-	-	-	6.3	17,300	100	?	?
M56	Lyra	-	-	-	-	X	X	X	X	X	X	X	-	8.3	32,900	85	?	?
M62	Ophiuchus	-	-	-	-	-	X	X	X	X	-	-	-	6.5	22,500	100	?	?
M68	Hydra	X	X	X	X	X	-	-	-	-	-	-	-	7.8	33,000	106	?	?
M69	Sagittarius	-	-	-	-	-	-	X	X	X	-	-	-	7.6	29,700	61	?	?
M70	Sagittarius	-	-	-	-	-	-	X	X	X	-	-	-	7.9	29,300	68	?	?
M71	Sagitta	-	-	-	-	-	X	X	X	X	X	X	-	8.2	13,000	27	?	?
M72	Aquarius	-	-	-	-	-	-	-	X	X	X	X	-	9.3	55,400	106	?	?
M75	Sagittarius	-	-	-	-	-	-	X	X	X	-	-	-	8.5	67,500	130	?	?
M80	Scorpius	-	-	-	-	-	X	X	X	-	-	-	-	7.3	32,600	95	?	?
M92	Hercules	-	-	-	-	X	X	X	X	X	X	-	-	6.4	26,700	109	?	14
M107	Ophiuchus	-	-	-	-	-	X	X	X	X	-	-	-	7.9	20,900	80	?	?

Data sources:

SEDS "Globular Clusters" website: www.seds.org/messier/glob.html
(note on ages: if several given, I've used the one attributed to Sky Catalog 2000)

Sky and Telescope Messier Card, 1997

Watson, Brent. Finder Charts of the Messier Objects, 1993

Harrington, Philip S. Touring the Universe Through Binoculars, Wiley, 1990

(Monthly availability determined from star charts in Rey, The Stars: a New Way to See Them and at Heavens-Above.com)