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Smithsonian Astrophysical Observatory

SAO exterior, Cambridge, Massachusetts

The Smithsonian Astrophysical Observatory (SAO) is a research institute of the Smithsonian Institution headquartered in Cambridge, Massachusetts, where it is joined with the Harvard College Observatory (HCO) to form the Harvard–Smithsonian Center for Astrophysics (CfA).


The SAO was founded in 1890 by Samuel Pierpont Langley, the Smithsonian's third Secretary, primarily for studies of the sun.[1] Langley is remembered today as an aeronautical pioneer, but he was trained as an astronomer and was the first American scientist to perceive "astrophysics" as a distinct field. Langley invented the bolometer and discovered infrared radiation from the sun.

In 1955, the SAO moved from Washington, D.C. to Cambridge, Massachusetts to affiliate with the Harvard College Observatory (HCO). The merger allowed the institution to expand staff, facilities, and scientific scope. Fred Whipple, the first director of SAO in this new era, accepted a national challenge to create a worldwide satellite-tracking network, a decision that would establish SAO as a pioneer and leader in space science research.[citation needed]

Smithsonian and the USAF Project Space Track shared observations and ephemerides throughout the early days of satellite tracking, 1957–1961.

In 1973, the ties between Smithsonian and Harvard were strengthened and formalized by the creation of the joint Harvard–Smithsonian Center for Astrophysics CfA.[2]

Remote stationsEdit

SAO has operated a number of remote stations over the years.[3][4]

Station Type Latitude Longitude El. (m) Opened Closed Coordinates
Mount Wilson, California Solar 34º13'N 118º56'W 1737 1908 1920 34°13′N 118°56′W / 34.217°N 118.933°W / 34.217; -118.933
Hump Mountain, North Carolina Solar 36º8'N 82º0'W 1500 1917 1918 36°8′N 82°0′W / 36.133°N 82.000°W / 36.133; -82.000
Calama, Chile Solar 22º28'S 68º56'W 2250 1918 1920 22°28′S 68°56′W / 22.467°S 68.933°W / -22.467; -68.933
Mount Montezuma, Chile Solar 22º40'S 68º56'W 2711 1920 ? 22°40′S 68°56′W / 22.667°S 68.933°W / -22.667; -68.933
Mount Harquahala, Arizona Solar 33º48'N 113º20'W 1721 1920 1925 33°48′N 113°20′W / 33.800°N 113.333°W / 33.800; -113.333
Table Mountain, California Solar 34º22'N 117º41'W 2286 1925 1962 34°22′N 117°41′W / 34.367°N 117.683°W / 34.367; -117.683
Mount Brukkaros, Namibia Solar 25º52'S 17º48'E 1586 1926 1931 25°52′S 17°48′E / 25.867°S 17.800°E / -25.867; 17.800
Mount Saint Catherine, Egypt Solar 28º31'N 33º56'E 2591 1934 1937 28°31′N 33°56′E / 28.517°N 33.933°E / 28.517; 33.933
Burro Mountain, New Mexico Solar 32º40'N 108º33'W 2440 1938 1946 32°40′N 108°33′W / 32.667°N 108.550°W / 32.667; -108.550
Organ Pass, New Mexico Space Track 32º25'N 253º27'E 32°25′N 106°33′W / 32.417°N 106.550°W / 32.417; -106.550
Olifantsfontein, South Africa Space Track 25º58'S 28º15'E 25°58′S 28°15′E / 25.967°S 28.250°E / -25.967; 28.250
Woomera, Australia Space Track 31º06'S 136º46'E 31°06′S 136°46′E / 31.100°S 136.767°E / -31.100; 136.767
Cadiz, Spain Space Track 36º28'N 353º48'E 36°28′N 6°12′W / 36.467°N 6.200°W / 36.467; -6.200
Shiraz, Iran Space Track 29º38'N 52º31'E 29°38′N 52°31′E / 29.633°N 52.517°E / 29.633; 52.517
Curaçao, Netherlands West Indies Space Track 12º05'N 291º10'E 12°05′N 68°50′W / 12.083°N 68.833°W / 12.083; -68.833
Jupiter, Florida Space Track 27º01'N 279º53'E 27°01′N 80°07′W / 27.017°N 80.117°W / 27.017; -80.117
Haleakala, Hawaii Space Track 20º43'N 203º45'E 20°43′N 156°15′W / 20.717°N 156.250°W / 20.717; -156.250
Villa Dolores, Argentina Space Track 31º57'S 294º54'E 31°57′S 65°06′W / 31.950°S 65.100°W / -31.950; -65.100
Mitaka, Japan Space Track
Nani Tal, India Space Track
Arequipa, Peru Solar,
Space Track
Oak Ridge Observatory

The SAO todayEdit

Currently, more than 300 scientists at the CfA are engaged in a broad program of research in astronomy, astrophysics, earth and space sciences, and science education.

SAO's pioneering efforts in the development of orbiting observatories and large ground-based telescopes, the application of computers to astrophysical problems, and the integration of laboratory measurements, theoretical astrophysics, and observations across the electromagnetic spectrum have contributed much to our current understanding of the universe.

The Chandra X-ray Observatory is managed and operated by SAO from Cambridge. With the University of Arizona, SAO also manages the MMT Observatory.



  1. ^ "SAO History". Retrieved 2015-09-03.
  2. ^ "About CfA". HARVARD & SMITHSONIAN CENTER FOR ASTROPHYSICS. Retrieved 2019-05-29.
  3. ^ Wright, F. W.; Hodge, P. W. (1965). "The Volcanic Dust Sampling Program of the Smithsonian Astrophysical Observing Stations". SAO Special Report #172 (1965). 172: 172. Bibcode:1965SAOSR.172.....W.
  4. ^ Roosen, Robert G.; Angione, Ronald J. (1977). "Variations in Atmospheric Water Vapor: Baseline Results from Smithsonian Observations". Publications of the Astronomical Society of the Pacific. 89: 814. Bibcode:1977PASP...89..814R. doi:10.1086/130233.
  5. ^ a b c d e f "SAO Directors: 1834 - Present". Smithsonian Astrophysical Observatory. Retrieved 2015-09-03.
  6. ^ "Charles Alcock Named Director of the Harvard-Smithsonian Center for Astrophysics". Harvard-Smithsonian Center for Astrophysics. Retrieved 2015-09-17.

External linksEdit