The Smithsonian Astrophysical Observatory (SAO) forms part of the Center for Astrophysics together with the Harvard College Observatory (HCO). Although SAO is headquartered on the Harvard campus, it is part of the same Smithsonian Institution whose museums line the Mall in Washington, D.C. The Smithsonian, which is a non-profit trust of the US federal government, was founded for the 'increase and diffusion of knowledge', and while all components of Smithsonian do both, the focus at SAO is mainly on the 'increase' part of that mandate as a key world center for ground-based and space-based astronomy and astrophysics.
Within the CfA, the bulk of the scientific staff are employed by SAO, and the major ground and space based observing facilities such as the Chandra X-ray Observatory are managed under SAO auspices. SAO operates as a government research laboratory but with the added benefit of close integration with Harvard, including access to both its facilities and its top-quality undergraduate and graduate students. In turn, the staff and students of HCO have access to the cutting-edge resources and broad expertise available at SAO.
Examples of current operating projects at SAO include the MMT optical telescope, the Submillimeter Array, as well as major involvement in a suite of NASA space missions including Chandra, Spitzer, Hinode, Kepler and SDO. In addition, SAO hosts key world astronomical resources such as the Astrophysics Data System (ADS) and the IAU Minor Planet Center, and develops widely used software such as the 'ds9' image display tool. Because the CfA operates scientifically as a single, integrated institution, the details of SAO activities are described on the general CfA web pages.
See also: A brief history of SAO