Photo by Pittendreigh
This cluster was observed long before Messier began his list. A. Ihle observed M22 in 1665, which would mean this is the first globular cluster that was known to astronomers.
Look between Xi and Lambda Sagittarii. On a very good, clear night, this spectacular globular cluster will be visible to the unaided eye.
WHAT TO LOOK FOR:
When looking for M22, the observer is looking for one of the best globular clusters. It has frequently been compared with M13 in Hercules.
Binoculars easily reveal the disk. Telescopes show a grainy, gritty area.
Look for strings of stars in the cluster.