The Otto Struve Telescope was the first major telescope to be built at McDonald Observatory. Located in the Davis Mountains in West Texas, the Otto Struve Telescope was designed by Warner & Swasey Company and constructed between 1933 and 1939 by the Paterson-Leitch Company. Its mirror was the second largest in the world at the time. It was named after the Russian-American astronomer Otto Struve in 1966, three years after his death; Struve had been the director of McDonald Observatory from 1932-1950.