Smithsonian Astrophysical Observatory

The Smithsonian Astrophysical Observatory or SAO is a large astronomical research facility of the Smithsonian Institution in Cambridge on the east coast of the USA. Together with the Harvard College Observatory (HCO ) it forms the Harvard - Smithsonian Center for Astrophysics ( CfA ).

The SAO was founded in 1890 in Washington, D.C. founded in 1955 but moved to Massachusetts in the technically leading the northeastern United States.

At the CfA are over 300 scientists and lots of technicians working in the areas of astronomy, astrophysics, earth science and space travel.

In the area of ​​space the Smithsonian Astrophysical Observatory has created long before the launch of the first earth satellite, the conditions for successful observations, including by the development of very high-intensity Baker - Nunn camera and foundation of the worldwide Moonwatch observer network.

Among the approximately 300 monographs on topics of astrophysics, aerospace and satellite geodesy developed in the 1960s Smithsonian Standard Earth stands out. It includes, inter alia, the first comprehensive analysis of the Earth's gravity field ( including its expansion in spherical harmonics up to degree 90) and was published from about 1965 in several volumes. All SAO publication series are in the - held A4 format and in a characteristic yellow- orange hue - for the U.S. rather unusual.

Also in the 1960s, the SAO catalog, a star catalog with 260,000 stars, from the then premier sources of data was created. Currently, among others, the Chandra X-ray observatory operated from Cambridge.