Open Cluster

Globular Clusters are some of the oldest objects in the universe. They formed at the beginning of the galaxy and continue to orbit them.  In most cases they are incredibly far away thus their smallish appearance in most telescopes. Globular Clusters area almost exclusively  very old yellow and small red stars.  They appear as small globes of stars. One of our first SETI messages was sent to globular cluster M-13 in the early 70's.  The return signal maybe a long term returning as M-13 is estimated to be 25,000 light years away. Also since the stars in M-13 are old population I they are poor in the elements required for life as we know it. 

Omega Centauri is the largest of the Globular Clusters that can be seen from the Northern Hemisphere. It is about 50 minutes in arcacross. This slightly less than the size of 2 full moons. It is also one of the closest as well. It is well placed for viewing on the southern horizon in late spring or early summer