New Telescope Aims to Get an Earful of ET

BERKELEY, CALIFORNIA--Astronomers listening for radio signals from other intelligent life in the universe may soon get their own ear on the cosmos. The Search for Extraterrestrial Intelligence (SETI) Institute of Mountain View, California, a private advocacy group that supports and carries out SETI studies, and the Radio Astronomy Laboratory at the University of California, Berkeley, announced today that they are teaming up to build the first major telescope largely dedicated to searching for other civilizations.

Called the One Hectare Telescope or 1HT because it will measure 100 meters on a side, the privately funded telescope will be built in the next 5 years or so, probably at Berkeley's Hat Creek Observatory in northern California. It will match the sensitivity of a single giant dish by combining the signals from 500 or more dishes just 3.5 to 5 meters across--essentially off-the-shelf satellite TV antennas. The design will allow the telescope to be expanded as funds become available. And it will cost a fraction as much as a comparable single-dish telescope: about $25 million, which the SETI Institute is now raising from private sources.

The 1HT should allow SETI researchers and more conventional observers collaborate seamlessly, because its design will allow "multibeaming." By interweaving the signals from its individual dishes in sophisticated ways, the array can make high-resolution observations simultaneously in 100 directions or more, to monitor an array of stars for signals from an extraterrestrial civilization while also studying pulsars, the intergalactic medium, and the cosmic background radiation. And to cast the broadest possible net for meaningful signals, the telescope will monitor each source across a wide range of the radio spectrum, from frequencies of 300 MHz up to 10 gigahertz.

The biggest design challenge, says William "Jack" Welch, who was just named to the newly created SETI chair in Berkeley's astronomy department and is also the vice president of the SETI Institute, is the sophisticated signal processing circuitry and software needed to combine and analyze hundreds of wide-band signals at once. "We couldn't [build] this before now," says Welch, "but we have every reason to believe that it can be done in the next year or two," when 1HT designers hope to install a prototype array of a dozen or so dishes at Hat Creek.