Smithsonian Astrophysical Observatory

Established on March 1, 1890 by Secretary Samuel P. Langley, the Smithsonian Astrophysical Observatory was one of the earliest to practice the "new astronomy," or astrophysics. Originally housed in a shed behind the Smithsonian Institution Building, the Castle, 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. Langley was director of the Astrophysical Observatory until his death in 1906.

Charles G. Abbot, who came to the observatory in 1895 as an assistant, was appointed director in 1907. Under Abbot's direction, several solar observing stations were established in the United States, South America, and Africa to carry out research on solar radiation. In 1929, then-Secretary Abbot established the Division of Radiation and Organisms to work with the Smithsonian Astrophysical Observatory on investigating the effects of radiation upon living organisms, mainly plants.

In 1955, the Smithsonian and Harvard University joined in an agreement to conduct astrophysical research, and the scientific headquarters of the Smithsonian Astrophysical Observatory moved to Cambridge, Massachusetts. Fred Lawrence Whipple, chairman of the Astronomy Department at Harvard, was named director, replacing director Loyal B. Aldrich, who retired. The move to Cambridge and a close alliance with the Harvard College Observatory generated an expansion of the Astrophysical Observatory’s research program.

Observatory staff were the first scientists able to locate and track the Soviet satellite Sputnik when it was launched in 1957. In the following years, contributions to the national space program were made by optical tracking of satellites at the observatory’s stations around the world. Orbiting astronomical observatory experiments, meteoritical and cometary studies, and theoretical astrophysics investigations were also undertaken.

A major Smithsonian Astrophysical Observatory facility located at Mount Hopkins, Arizona, was opened in 1968. The Multiple-Mirror Telescope, a joint project of the observatory 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.

In 1973, the Smithsonian and Harvard University established the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, to coordinate the related research activities of the Smithsonian Astrophysical Observatory and the Harvard College Observatory under a single director. The consolidated Center for Astrophysics research program was organized into seven divisions: Atomic and Molecular Physics; High Energy Astrophysics; Optical and Infrared Astronomy; Planetary Sciences; Radio and Geoastronomy; Solar and Stellar Physics; and Theoretical Astrophysics. Major Smithsonian Astrophysical Observatory studies in hydrogen masers, submillimeter wavelength interferometers, and infrared telescopes were undertaken in the 1970s and 1980s. On November 22, 2003, the Smithsonian Astrophysical Observatory dedicated the Submillimeter Array atop Mauna Kea, Hawaii. The Submillimeter Array explores the universe by detecting light of colors which are not visible to the human eye, furthering the observation programs first established by Samuel Langley in 1890.

Further Exploration

• Chronology of the Smithsonian Astrophysical Observatory
• Bibliography of the Smithsonian Astrophysical Observatory
• Images of the Smithsonian Astrophysical Observatory

Related Collections

• Smithsonian Astrophysical Observatory Records from the Smithsonian Institution Archives
• Historic Picture Highlights of the Smithsonian Astrophysical Observatory
• Additional Records and Collections of the Smithsonian Astrophysical Observatory Across the Smithsonian    

Other Resources

• Smithsonian Astrophysical Observatory Website
• Harvard-Smithsonian Center for Astrophysics Milestones
• More about the History of the Harvard-Smithsonian Center for Astrophysics