The setting sun shines on Palomar Observatory. As the sun sets the dome is opened and astronomers start to prepare equipment for a night of cosmic exploration. The huge dome is 42 meters in diameter (see the person at the base of the dome for scale). The Observatory is located in north San Diego County, California. Founded in 1930s it is still a world-class research center. The observatory is home to five telescopes including the 200-inch (5 meters) Hale telescope and its giant dome which is photographed above. The 200-inch telescope is named after astronomer George Ellery Hale who led the making of the world's largest telescopes in the first half of 20th century. Hale telescope saw first light in 1949 and astronomer Edwin Hubble was the first astronomer to use it. The 200-inch telescope was the world's largest for nearly 3 decades and updated with adaptive optics and high technology detectors it is still considered a frontier observing instrument.