Globular Cluster M22

Those of us who live in the southern U.S. have an excellent view of M22 in the southern sky. Though globular cluster M13 gets top billing in the U.S., M22 is significantly bigger in apparent diameter. It's therefore more impressive in small telescopes, being easier to resolve into individual stars. Only two other globulars outshine M22, both far to the south (Omega Centauri and 47 Tucanae).

M22 is believed to contain half a million stars. It's located toward the center of our Milky Way galaxy, so there is a lot of intervening dust. It is believed that M22 would be five times brighter otherwise (imagine that!). Nevertheless it's visible to the naked eye under dark skies far south. Of course at my house I can't see globulars very well even in the telescope. But CCD cameras are wonderful, and the photos below came out nice.

Globular Cluster M22
(Click image to enlarge)

Object Details:

Type: Globular star cluster
Constellation: Sagittarius
Distance: 10,400 light-years
Diameter: 97 light-years

Upper Image Details:

Date:  June 05, 2005
Site: Harahan, LA
Conditions:  Hazy
Exposure: CCD, 5x 2 min.
Filters: Orion SkyGlow LPR
Processing: MSB Astroart 3.0
Telescope: 4" Tak FSQ-106N
Reducer:  None (f/5.0)
CCD: Starlight Express MX7C
Autoguider: S.T.A.R. 2000

Lower Image Details:

Date: August 13, 2004
Site: Harahan, LA
Exposure: CCD, 10 x 2 min.
Filters: Orion SkyGlow LPR
Processing: MSB Astroart 3.0
Telescope: 10" Meade LX200
Reducer: Meade, f/4.3
CCD: Starlight Express MX7C
Autoguider: S.T.A.R. 2000

For more on globular clusters, see my M13 (Hercules) Globular Cluster page.