Mount Wilson Observatory

The Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a 5,710-foot peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles.

The observatory contains two historically important telescopes: the 100-inch (2.5 m) Hooker telescope, which was the largest aperture telescope in the world from its completion in 1917 to 1949, and the 60-inch telescope which was the largest operational telescope in the world when it was completed in 1908.

The observatory was conceived and founded by George Ellery Hale.