FACTBOX: What's at stake on Mt. Wilson with wildfire

(Reuters) - The wildfire burning in the mountains of Los Angeles is perilously close to Mount Wilson, home to a landmark observatory and the communications nexus for Southern California.

If fire engulfs the 40-acre (16 hectare) site and its 50 buildings 5,700 feet above Pasadena, the following might be damaged:

* Mt. Wilson Observatory was founded in 1904 and founder George Ellery Hale used the 60-inch tower telescope to discover magnetic fields around the sun. It is still in operation today and houses multimillion-dollar astronomy projects.

* The observatory was also home to Edwin Hubble, who used the 100-inch Hooker telescope in the 1920s to observe distant galaxies and develop his theory that the universe was expanding. That, together with Einstein's theory of relativity, led to the Big Bang theory -- that the universe was created at a specific point in time.

* Cell phone operators reportedly have equipment on Mt. Wilson, but the top three U.S. mobile services -- Sprint, AT&T and Verizon Wireless -- all say they don't have equipment on the summit.

* Mt. Wilson is home to more than two dozen towers that support broadcast antennas for beaming signals. While most television is now delivered by cable or satellite, FM radio broadcasts could be hampered by the fire.

* Some emergency law enforcement communication is also transmitted through Mt. Wilson.

(Compiled by Mary Milliken, editing by Dan Whitcomb and Todd Eastham)