The Smithsonian Astrophysical Observatory (SAO) is a research institution located in Cambridge, Massachusetts. It is part of the Smithsonian Institution and focuses on the study of astronomy and astrophysics. Established in 1890, the observatory conducts scientific research and provides educational resources to the public. SAO is known for its contributions to various fields, including stellar astrophysics, cosmology, and planetary science. It operates several telescopes and collaborates with other institutions to advance our understanding of the universe. The observatory also plays a key role in the Harvard-Smithsonian Center for Astrophysics, which combines research and education in the field.