The Smithsonian Astrophysical Observatory (SAO) is a research institute of the

Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Found ...

, concentrating on astrophysical studies including galactic and

extragalactic astronomy Extragalactic astronomy is the branch of astronomy concerned with objects outside the Milky Way galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy. The closest objects in extragalactic ...

cosmology Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', and in 1731 taken up in Latin by German philosopher ...

, solar, earth and planetary sciences,

theory A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may ...

and instrumentation, using observations at wavelengths from the highest energy

gamma rays A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...

to the

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a tr ...

, along with

gravitational waves Gravitational waves are waves of the intensity of gravity generated by the accelerated masses of an orbital binary system that propagate as waves outward from their source at the speed of light. They were first proposed by Oliver Heaviside i ...

. Established in Washington, D.C., in

1890 Events January–March * January 1 ** The Kingdom of Italy establishes Eritrea as its colony, in the Horn of Africa. ** In Michigan, the wooden steamer ''Mackinaw'' burns in a fire on the Black River. * January 2 ** The steamship '' ...

, the SAO moved its headquarters in 1955 to

Cambridge, Massachusetts Cambridge ( ) is a city in Middlesex County, Massachusetts, United States. As part of the Boston metropolitan area, the cities population of the 2020 U.S. census was 118,403, making it the fourth most populous city in the state, behind Boston, ...

, where its research is a collaboration with the Harvard College Observatory (HCO) and the

Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of highe ...

Department of Astronomy. In 1973, the Smithsonian and Harvard formalized the collaboration as the Center for Astrophysics , Harvard & Smithsonian (CfA) under a single Director.

History

Samuel Pierpont Langley, the third Secretary of the Smithsonian, founded the Smithsonian Astrophysical Observatory on the south yard of the

Smithsonian Castle The Smithsonian Institution Building, located near the National Mall in Washington, D.C. behind the National Museum of African Art and the Sackler Gallery, houses the Smithsonian Institution's administrative offices and information center. The ...

(on the U.S.

National Mall The National Mall is a landscaped park near the downtown area of Washington, D.C., the capital city of the United States. It contains and borders a number of museums of the Smithsonian Institution, art galleries, cultural institutions, and va ...

) on March 1,

. The Astrophysical Observatory's initial, primary purpose was to "''record the amount and character of the Sun's heat''".

Charles Greeley Abbot Charles Greeley Abbot (May 31, 1872 – December 17, 1973) was an American astrophysicist and the fifth secretary of the Smithsonian Institution, serving from 1928 until 1944. Abbot went from being director of the Smithsonian Astrophysical Ob ...

was named SAO's first director, and the observatory operated

solar telescope A solar telescope is a special purpose telescope used to observe the Sun. Solar telescopes usually detect light with wavelengths in, or not far outside, the visible spectrum. Obsolete names for Sun telescopes include heliograph and photoheliograp ...

s to take daily measurements of the Sun's intensity in different regions of the optical electromagnetic spectrum. In doing so, the observatory enabled Abbot to make critical refinements to the

Solar constant The solar constant (''GSC'') is a flux density measuring mean solar electromagnetic radiation ( total solar irradiance) per unit area. It is measured on a surface perpendicular to the rays, one astronomical unit (au) from the Sun (roughly the ...

, as well as to serendipitously discover Solar variability. It is likely that SAO's early history as a solar observatory was part of the inspiration behind the Smithsonian'
"sunburst" logo
designed in 1965 by Crimilda Pontes. In 1955, the scientific headquarters of SAO moved from Washington, D.C. to

to affiliate with the Harvard College Observatory (HCO).

Fred Lawrence Whipple Fred Lawrence Whipple (November 5, 1906 – August 30, 2004) was an American astronomer, who worked at the Harvard College Observatory for more than 70 years. Amongst his achievements were asteroid and comet discoveries, the " dirty snowball" h ...

, then the chairman of the Harvard Astronomy Department, was named the new director of SAO. The collaborative relationship between SAO and HCO therefore predates the official creation of the CfA by 18 years. SAO's move to Harvard's campus also resulted in a rapid expansion of its research program. Following the launch of ''

Sputnik Sputnik 1 (; see § Etymology) was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program. It sent a radio signal back to Earth for ...

'' (the world's first human-made satellite) in 1957, SAO accepted a national challenge to create a worldwide satellite-tracking network, collaborating with the

United States Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Si ...

on Project Space Track. With the creation of

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeedin ...

the following year and throughout the

space race The Space Race was a 20th-century competition between two Cold War rivals, the United States and the Soviet Union, to achieve superior spaceflight capability. It had its origins in the ballistic missile-based nuclear arms race between the t ...

, SAO led major efforts in the development of orbiting observatories and large ground-based telescopes, laboratory and theoretical astrophysics, as well as the application of computers to astrophysical problems.

Remote stations

SAO has operated a number of remote stations over the years.

SAO Today

The current director of the SAO is

Lisa Kewley Lisa Jennifer Kewley (born 1974) is a Professor and Director of the ARC Centre of Excellence for All Sky Astrophysics in 3-D (ASTRO 3-D) and ARC Laureate Fellow at the Australian National University College of Physical and Mathematical Science ...

(2022 to present). There are currently about 170 research staff working at the SAO, including affiliated research staff. In addition, the SAO has about 120 postdoctoral researchers/fellows working in five competitive, associated fellowship programs: CfA, Clay, SMA, ITAMP, and Leon Van Speybroeck, or in support of a contract or grant. (Additional postdocs do research via Harvard fellowship programs or national/international fellowship awards); about 40% of the postdoctoral community are women and about 12% are from minority populations. SAO scientists can supervise

Harvard Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...

Ph.D students, and in addition they typically supervise about 30 graduate students from other institutions who are pursuing Ph.D. theses at the SAO. About thirty undergraduate students intern at the SAO each year. All together there are about 950 staff (including administrative and management department employees) working at the Center. Black hole - Messier 87 crop max res

Directors

* Samuel Pierpont Langley 1890–1906 *

1906–1942 *

Loyal Blaine Aldrich Loyal Blaine Aldrich (November 20, 1884 – February 11, 1965) was an American astrophysicist and astronomer of the Smithsonian Institution. Upon graduation from the University of Wisconsin in 1907, Aldrich became a Smithsonian Astrophysica ...

1942–1955 *

1955–1973 * George B. Field 1973–1982 (with the creation of the Harvard-Smithsonian Center for Astrophysics in 1973, the director of SAO and the Harvard College Observatory became a joint position) * Irwin I. Shapiro 1982–2004 * Charles R. Alcock 2004–2022 *

2022–

Associates

* Margaret Sordahl

References

External links

*
SAO homepageCenter for Astrophysics , Harvard & Smithsonian
{{Authority control Buildings and structures in Cambridge, Massachusetts

Astronomical observatories in Massachusetts Mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different ele ...

Smithsonian Institution research programs Harvard–Smithsonian Center for Astrophysics Research institutes in Massachusetts