The Smithsonian/NASA Astrophysics Data System
Bibliographic databases containing more than 5 million records. Includes full-text scans of much of the astronomical literature of the past century.
ARIBIB
The ARI Bibliographical Database for Astronomical References (ARIBIB) of the Astronomisches Rechen-Institut (Heidelberg) will in the near future provide a nearly complete online bibliography of the astronomical literature from the earliest times up to the year 2000.
AAS Obituary Index
Obituaries published in the Bulletin of the American Astronomical Society, with links to those available online.
The MacTutor History of Mathematics archive Extensive biographies and essays on historical topics. The definition of mathematicians is sufficiently elastic to include Edwin Hubble, and the topics include mathematical astronomy.
The Bruce Medalists
Photos, brief biographies, and extensive bibliographies of approximately 100 astronomers honored since 1898 by the Astronomical Society of the Pacific.
The Shapley-Curtis Debate in 1920 A number of articles and bibliographies related to the famous “debate” on the Scale of the Universe.
A Brief History of High Energy Astronomy
Provided by High Energy Astrophysics Science Archive Research Center (HEASARC), includes dates of missions, and even ancient astronomy-related events.
History of Astronomy
by Wolfgang R. Dick. Although not updated much recently, this remains the most complete website devoted to the history of astronomy.