Armagh Observatory History and Architecture
Instuments, astronomers, a list of original sources archived.
http://www.arm.ac.uk/history/

Dudley Observatory
Library, archives, outreach programs.
http://www.dudleyobservatory.org/

History of the Leander J. McCormick Observatory
Early astronomy at the University of Virginia.
http://www.astro.virginia.edu/research/observatories/26inch/history/