Agency history, 1890-

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  • Langley, S. P (Samuel Pierpont) 1834-1906
  • Whipple, Fred L (Fred Lawrence) 1906-2004
  • Abbot, C. G (Charles Greeley) 1872-1973
  • Aldrich, Loyal Blaine 1884-1965
  • Field, George B. 1929-
  • Shapiro, Irwin I
  • Alcock, Charles
  • Harvard-Smithsonian Center for Astrophysics
  • Smithsonian Institution
  • Smithsonian Institution Building (Washington, D.C.)
  • Harvard University


Agency History


  • This is an agency history. It does not describe actual records. The Smithsonian Institution Archives uses these histories as brief accounts of the origin, development, and functions of an office or administrative unit to set that unit in its historical context. To find information on record holdings, please double-click the highlighted field "Creator/Author", which will open on a brief view of relevant records.
  • Guide to the Smithsonian Archives 1996
  • Smithsonian Institution, "Smithsonian Astrophysical Observatory," [],01/07/00
  • Center for Astrophysics, Harvard and Smithsonian, SAO and CfA Directors; 1834-Present,, accessed July 28, 2021.
  • The Smithsonian Astrophysical Observatory (SAO) was established in 1890, by Secretary Samuel P. Langley, as a research unit of the Smithsonian Institution concentrating on studies of solar radiance. It was one of the earliest to practice the "new astronomy," or astrophysics. Originally housed in a shed behind the Smithsonian Institution Building, the Observatory initially focused its research on the study of solar radiation and the solar constant - the amount of energy from the sun that strikes the outer edge of the earth's atmosphere. In the early twentieth century, several observing stations were established in the United States, South America, and Africa to carry out research on solar radiation.
  • In 1955, the Smithsonian and Harvard University joined in an agreement to conduct astrophysical research, and the scientific headquarters of SAO was moved to Cambridge, Massachusetts. The move to Cambridge and a close alliance with the Harvard College Observatory generated an expansion of the SAO research program. Contributions to the national space program were made by optical tracking of satellites at SAO stations around the world. Orbiting astronomical observatory experiments, meteoritical and cometary studies, and theoretical astrophysics investigations were also undertaken. A major SAO observatory located at Mount Hopkins, Arizona, was opened in 1968. The Multiple-Mirror Telescope, a joint project of SAO and the University of Arizona, was dedicated at Mount Hopkins in 1979. The Mount Hopkins Observatory was renamed the Fred Lawrence Whipple Observatory in 1981, who was the Chairman of the Astronomy Department at Harvard and later became Director of SAO.
  • On July 1, 1973, the Smithsonian Institution and Harvard University established the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge to coordinate the related research activities of the two observatories under a single director. Today, both observatories retain their separate identities, each responsible to its parent organization; however, the joint venture draws on the coordinated strengths of the two organizations and the combined staffs in seven research divisions: Atomic and Molecular Physics, and Theoretical Astrophysics. In addition, the CfA has a department devoted to science education.
  • Two abbreviations have been used in reference to the Smithsonian Astrophysical Observatory, APO (Astrophysical Observatory) and SAO. The use of SAO began sometime after the move to Cambridge.
  • Samuel P. Langley was director of SAO unitl 1906. Charles G. Abbot served as director from 1907-1944. Abbot was followed by Loyal Blaine Aldrich, 1944-1955; Fred L. Whipple, 1955-1973; George B. Field, 1973-1983; Irwin I. Shapiro, 1983-2004; and Charles Alcock, 2004- .

Repository Loc.

Smithsonian Institution Archives, Capital Gallery, Suite 3000, MRC 507; 600 Maryland Avenue, SW; Washington, DC 20024-2520


  • 1890
  • 1890-


  • Observatories
  • Astrophysical observatories


Mixed archival materials

Local number

SIA AH00010

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