Astrophysical Observatory in South Yard, by Unknown, 1909, Smithsonian Archives - History Div, The Smithsonian Astrophysical Observatory located in the South Yard behind the south facade of the Smithsonian Institution Building. The Astrophysical Observatory is enclosed by a wooden fence. The Annex, also called the South Shed, is behind the Observatory. The Laboratory of Natural History, the old Agriculture Building, and the Washington Monument are visible in the background..