The Harvard College Observatory, founded in 1839 by William C. Bond, is located in Cambridge, Mass. It has a major field station, called the G.R. Agassiz Station, at Ft. Davis, Tex. Together with the Smithsonian Astrophysical Observatory it forms the Harvard-Smithsonian Center of Astrophysics. Observatory instruments include a 26-m (85-ft) radio telescope at Ft. Davis. Although no longer in use, the Cambridge location still houses a 38-cm (15-in) refractor, erected in 1847, that was the largest refractor in the United States until 1863.Astronomers at Harvard College Observatory began compilation of the Henry Draper Catalogue of stars in the late 1880s. The Harvard Classification of Stars, a system based on spectral type that resulted from this work, is still in use.