Don Bouc Astrophotography

* Globular Star Clusters - A globular cluster is a spherical collection of stars that orbit a galactic core, as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes, and relatively high stellar densities toward their centers.  Globular clusters are found in the halo of a galaxy and contain considerably more stars, and are much older, than the less dense, open clusters which are found in the disk of a galaxy.  Globular clusters are fairly common; there are about 250 currently known globular clusters in the Milky Way, with, perhaps, 10 to 20 more, still undiscovered.  Larger galaxies can have more: The Andromeda Galaxy, for instance, may have as many as 500.  Some giant elliptical galaxies (particularly those at the centers of galaxy clusters), such as Messier 87, have as many as 13,000 globular clusters.

 

* Open Star Clusters - An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way Galaxy, and many more are thought to exist.  Some of these clusters still have gas and dust surrounding or near them that create an sort of embedded  reflection nebula.

 

 

​