Atop 6,000-foot Palomar Mountain, the observatory is owned and operated by the California Institute of Technology, whose astronomy faculty conducts research here. The observatory houses the Hale Telescope, as well as 60-inch, 48-inch, 24-inch, 18-inch, and Snoop telescopes. Some of the most important astronomical discoveries of the 20th century were made here, and already in this century scientists using the observatory's 48-inch telescope have detected a 10th planet.
The observatory closes without advance notice during inclement weather. Call in advance during winter. The small museum contains photos of some of these discoveries, as well as photos taken by NASA's Hubble Space Telescope and from recent NASA–European Space Agency missions to Mars and Saturn. A park with picnic areas surrounds the observatory.
Rte. S6 north of Rte. 76, east of I–15, 35899 Canfield Rd., Palomar Mountain, California, 92060, United States