Astronomical observatory on Mount Palomar, near San Diego, California, U.S., site of the famous Hale telescope , a reflecting telescope with a 200-in.
(5-m) aperture that has proved instrumental in cosmological research. Built in 1948 and named in honour of George Ellery Hale (1868–1938), it was the largest instrument of its kind for almost 30 years. Founded in 1948 by California Institute of Technology, the observatory was operated jointly with the Mount Wilson Observatory as the Hale Observatories until 1980.