
http://pursn3.physics.purdue.edu/becker/cluster.html
Photometric Analysis of Open Star Clusters
The Messier Catalog
http://fusedweb.pppl.gov/CPEP/Chart_Pages/5.Plasmas/Nebula.html
Nebulae: Fuzzy Patches In Space
http://www.seds.org/messier/hottest.html
The Hottest Messier Stuff Available
http://cfa-www.harvard.edu/cfa/ps/cbat.html
IAU Circulars
http://seds.lpl.arizona.edu/billa/twn/top.html
The Web Nebulae
http://seds.lpl.arizona.edu/messier/data.html
Messier Objects, all 103 (+7) of them.