A new telescope at an observatory outside Boston will become a key tool in the search for extraterrestrials as scientists try to detect light signals from distant civilizations.

An optical telescope dedicated Tuesday at the Oak Ridge Observatory, about 35 miles west of Boston, is the first to be used exclusively for a project called the Search for Extraterrestrial Intelligence.

The 22-year-old SETI project has largely relied on radio telescopes to search for radio signals from outer space that could indicate the presence of intelligent beings.

While some scientists are skeptical that such an approach could yield such evidence, the scientists who will use the Oak Ridge telescope believe extraterrestrials may be just as likely to communicate with high-intensity, tightly focused light beams carrying information as they are to use radio transmissions.

"If I were a betting man, I'd bet radio would work before light," said Paul Horowitz, a Harvard physicist who heads a SETI project at the university. "But we've done that for 20 years, and we haven't explored much with light."

Scientists began using optical telescopes on the SETI project in 1998 at Oak Ridge and other sites. Until now, they've had to share time on optical telescopes with other astronomers doing different work. The new telescope will be scan the night skies uninterrupted and exclusively for SETI.

Harvard graduate students at the school's Cambridge campus will remotely analyze data from the telescope, searching for light patterns that could indicate an intentional communication.

Older optical telescopes weren't well-suited for the broad searching of the heavens that scientists will undertake at Oak Ridge.

The new telescope has a 72-inch mirror — larger than any U.S. telescope east of the Mississippi River — and other features that will enable scientists to scan the heavens more than 500 times faster than older telescopes, Horowitz said.

"It's like a bug-eyed monster view of the universe, rather than looking through a soda straw," he said.

The telescope was purchased with a $350,000 award from The Planetary Society, a Pasadena, Calif.-based nonprofit that supports SETI.

One self-described SETI skeptic said the light signal approach to searching the heavens is even less likely to detect signs of any distant civilization than the radio approach.

UCLA astronomer Ben Zuckerman said dust from extinct stars absorbs much of the light from the far reaches of the universe where any such civilization is likely to be present. Radio signals aren't absorbed by dust, and are easier to detect.

The other reason for Zuckerman's skepticism is far more earthly — he believes Massachusetts' often-cloudy skies will only infrequently yield clear views of space from an earthbound observatory.