Lick Observatory, the astronomical observatory of the University of California. It stands some 4,200 feet (1,280 m) above sea level on the summit of Mount Hamilton, about 25 miles (40 km) east of San Jose. The observatory, completed in 1888, was endowed and given to the state as a division of the University of California by James Lick (1796-1876), an American financier and philanthropist.

In 1874, Lick placed property worth $3,000,000 in the hands of the trustees with instructions that $700,000 should be used in purchasing and housing a powerful telescope, superior to and more powerful than any telescope yet made. The Mount Hamilton site was chosen because of the clear atmosphere.

When installed in 1888, the observatory's 36-inch (914-mm) refracting telescope fulfilled James Lick's orders for the world's largest telescope. It remains in constant use and among refractors is second in size only to the 40-inch (1,016-mm) lens built at Yerkes Observatory in the 1890's. Lick's major telescope is a 120-inch (3,048-mm) reflector completed in 1959. Other instruments include a 20-inch (508-mm) astrographic camera (a telescope used to determine exact star positions) and a 36-inch (914-mm) reflector.

Aided by the skill of such noted astronomers as Edward E. Barnard and E. S. Holden, Lick Observatory was a pioneer in the observation and charting of stars and galaxies. Barnard also discovered one of Jupiter's moons and was the first astronomer to detect a comet by photography. Lick astronomers have carried out studies of double stars, variable stars, and motions of stars and galaxies.