The Bruce Medalists


  Photo 1955, courtesy Mt. Wilson Observatory
Wilhelm Heinrich Walter Baade
24 March 1893 1955 Bruce Medalist 25 June 1960

Born in Germany and educated at Göttingen, Walter Baade worked at the Hamburg Observatory from 1919 to 1931 and at Mt. Wilson from 1931 to 1958. He and Fritz Zwicky proposed in 1934 that supernovae could produce cosmic rays and neutron stars, and Baade made extensive studies of the Crab Nebula and its central star. During World War II blackouts of the Los Angeles area Baade used the 100-inch Hooker telescope to resolve stars in the central region of the Andromeda Galaxy for the first time. This led to his definition of two stellar populations, to the realization that there were two kinds of Cepheid variable stars, and from there to a doubling of the assumed scale of the universe. Baade and Rudolph Minkowski identified and took spectrograms of optical counterparts of many of the first-discovered radio sources, including Cygnus A and Cassiopeia A. Baade discovered the asteroids Hidalgo and Icarus.

Presentation of Bruce medal
Wilson, Olin C., PASP 67, 56-71 (1955).

Other awards
American Astronomical Society, Henry Norris Russell Lectureship, 1958.
Royal Astronomical Society, Gold medal, 1954, presented by J. Jackson, MNRAS 114, 370 (1954).

Biographical materials
Borgelt, Gerda-Ilke, “Zum Geburtstag von Walter Baade”
Club Astronomique du Val de Loir [in French]
Dieke, Sally H., Dictionary of Scientific Biography 1, 352-54.
Florence, Ronald, Biographical Encyclopedia of Astronomers (Springer, NY, 2007), pp. 73-74.
Osterbrock, Donald E., “Walter Baade, Observational Astrophysicist”
   (1): “The Preparation 1893-1931,” Journal for the History of Astronomy 26, 1-32 (1995).
   (2): “Mount Wilson 1931-1947,” Journal for the History of Astronomy 27, 301-348 (1996).
   (3): “Palomar and Göttingen 1948-1960 (Part A),” Journal for the History of Astronomy 28, 283-316 (1997).
   (3): “Palomar and Göttingen 1948-1960 (Part B),” Journal for the History of Astronomy 29, 345-77 (1998).
Osterbrock, Donald E., Walter Baade: A Life in Astrophysics (Princeton University Press, 2001).
Osterbrock, Donald E., “Walter Baade, Master Observer,” Mercury 31, 4, 32-41 (2002) [abstract].
Richardson, Robert S., The Star Lovers (Macmillan, NY, 1967).
Schmidt-Kaler, Theodor, “Walter Baades Wissenschaftliche Genealogie,” Die Sterne 70, 2, 90-100 (1994).
Schmidt-Kaler, Theodor, “Baades Arbeiten und ihre Bedeutung in der Perspektive der historische Entwicklung,” Die Sterne 70, 5, 277-85 (1994).
Sharov, A.S., “Walter Baade - A Remarkable Astronomer-Observer of the 20th Century,” Istoriko-Astronomicheskie Issledovaniya 26, 98-148, 262 (2001) [in Russian. Abstract].

Arp, Halton C., JRASC 55, 113-16 (1961).
Heckmann, Otto, Mitteilungen der Astronomischer Gesellschaft 94, 5-11 (1961) [includes list of Baade’s publications].
Sandage, Allan, QJRAS 2, 118-21 (1961).
Schoenberg, E., Bayerische Akademie der Wissenschaftern Jahrbuch, 1960 177-81.
Wachmann, A.A., Die Sterne 36, 204-07 (1960).
More obituaries

American Association of Variable Star Observers (AAVSO)
Astronomical Society of the Pacific (Huntington Library photo)
Caltech Archives
AIP Center for History of Physics
Friedman, Jon R., Portrait Sketch
Hamburg Observatory
Memorial plaque placed on Baade’s grave in 2003

Named after him
Lunar crater Baade
Minor Planet #1501 Baade
Baade’s Window
The Walter Baade Telescope (formerly Magellan I)

More references

The Bruce Medalists

Please send comments, additions, corrections, and questions to