This gallery contains images of open clusters and globular clusters. An open cluster is a smallish grouping of stars (up to a few thousand) that were formed from the same molecular cloud, and are still loosely bound by gravity. A globular cluster is a large, spherical collection of stars that orbits a galaxy as a satellite. More information can be found in the Wikipedia entries for open cluster and globular cluster.
Thanks, I have taken one or two modest shots with a regular lens and tripod, and I appreciate the work that has gone in these photos.
Thanks for sharing