Lacaille's Catalog of Nebulae of the Southern Sky «
http://www.seds.org/messier/xtra/history/lacaille.html | | A discussion of lacaille's catalog , which is mainly of historical interest. includes the catalog itself. |
Star Clusters «
http://www.seds.org/messier/cluster.html | | General information on star clusters from seds. |
Stellar Clusters «
http://www-astronomy.mps.ohio-state.edu/~ryden/ast162_4/notes17.html | | Lecture notes by professor barbara ryden. |
