Milky Way
Globular
Clusters
Index
1. Introduction
2. Orbits
3. Omega Centauri
4. 47 Tucanae
5. 47 Tuc Core
6. 47 Tuc Blue Stragglers
7. M4
8. M5
9. M10
10. M13
11. M15
12. M22
13. NGC 6522
14. Galactic Centre Chart
15. List of MW Globulars
16. Credits and Links
M22
Image credit: N.A.Sharp, REU program/NOAO/AURA/NSF
M22 or NGC 6656 is an elliptical globular cluster in the constellation Sagittarius near the Galactic bulge region. It is one of the brightest globulars in the night sky. M22 was one of the first globulars to be discovered (in 1665 by Abraham Ihle). It was one of the first globular clusters to be carefully studied, beginning with Harlow Shapley in 1930.
At a distance of about 10,000 light-years, M22 is one of the nearer globular clusters. Despite its relative proximity to us, this metal-poor cluster's light is affected by dust extinction. It[s angular diameter is 32', which translates to a spatial diameter of around 100 light-years.
Its location in front of the galactic bulge has led to its use in microlensing detection of very faint objects in the far distant star fields of the bulge.
Sources:
Messier 22 - Wikipedia
Hubble Site, as cited in the text