Lights out

HARVARD -- The hazy orange glow of light pollution that has thickened like a cataract over Greater Boston in the last decade is helping to push the last great telescope in New England out of business.

The Smithsonian Institution is to pull funding from the Oak Ridge Observatory -- the largest optical telescope in the country east of Texas -- at the end of the summer. The move would end a 25-year relationship with Oak Ridge and, most likely, the life of a scope that has anchored observational astronomy research in New England since 1933.

Set on a clearing atop a 700-foot ridge 30 miles west of Boston, the three-story observatory was the first to detect a planet beyond our solar system. But, over the last 10 years, astronomers say the area's worsening light pollution, driven by development, has limited their ability to observe distant and dim stars. That, in turn, has reduced the number of researchers able to use the scope, whose mirror measures 5-feet across, diminishing the observatory's usefulness.

''If you only have a small group of people using the telescope, you're more vulnerable to cuts," said Robert Stefanik, director of Oak Ridge, which is owned by the Harvard-Smithsonian Center for Astrophysics.

While community groups have shown interest in taking over the observatory, Charles Alcock, director of the Harvard-Smithsonian center, said the telescope probably will be dismantled for liability reasons. Harvard University will continue to own the land and to conduct other research projects there.

''There's a real sadness to shutting something like this down," Alcock said, ''but we have an obligation to the taxpayers who support us to make the best use of our money, and Oak Ridge isn't the best use anymore."

The observatory, which sits in a building that looks like a giant beer can with a retractable roof, costs about $6,000 a year to maintain and substantially more than $100,000 a year to staff, according to Alcock and David Latham, a senior astronomer at the Smithsonian and former associate director of Oak Ridge. The closing will cost two astronomers their jobs. There are currently about three-dozen active projects at the observatory, with about 50 partners all over the world.

The observatory is still useful, Latham said, but there is always pressure in astronomy to move forward with the next new thing. In this case, Latham said, that's the $100 million Magellan Observatory, in the Chilean Andes, where there are two optical telescopes, each more than four-times the diameter of the Oak Ridge scope, built at 8,000 feet elevation, under some of the clearest skies on Earth.

New England's skies, meanwhile, have become increasingly polluted. Oak Ridge was built in the early 1930s because the city lights were beginning to limit Harvard University's telescope in Cambridge. Back then, before the construction of the Massachusetts Turnpike or Interstate 495, the community of Harvard was still deep in the countryside.

But in the '90s, light pollution started spreading over the ridgeline where the observatory sits, and began forcing astronomers to adapt their research.

''Light pollution is the curse of astronomy," Alcock said. ''It seems that wherever we put our telescopes, sooner or later civilization catches up with us."

The phenomenon has long frustrated astronomers and environmentalists, especially as the pace of development quickened and tens of thousands more streetlights were lit. This glow overwhelms the fainter light from the heavens.

State legislation to minimize the most overt causes of light pollution -- street lights that leak 30 percent of their wattage skyward -- has been filed five times by Arlington Rep. James Marzilli since 1993, but has never passed. Marzilli and astronomers want to put shades on newly installed streetlights, to concentrate their light downward, but the light manufacturing industry has opposed the move.

Meanwhile, sky glow is exacerbated over Boston because the Jet Stream drags so much of the country's air pollution over the region -- so much that New England has been called the ''tailpipe of the nation."

In the most pristine conditions, there are as many as 6,000 stars visible to the naked eye. Over most of North America, on a clear night, between 1,000 and 2,000 stars can be seen, Stefanik said. Most nights, no more than a few dozen stars are visible in the Boston area.

''What we're losing is the ability to look up and wonder who our neighbors are," said Kelly Beatty, editor of Night Sky Magazine, which is headquartered in Cambridge. ''We don't ask ourselves the big questions when we can't see the heavens. And those questions inspire us and force us to think of ourselves in a larger context."

Dan Green, an astronomer at the Harvard-Smithsonian center and a member of the New England Light Pollution Advisory Group, said when his children were recently assigned an astronomy project to find a constellation, they came to him for help because they could not.

''It's just really kind of sad," he said. ''Imagine taking away all the trees or all the birds."

Through the first 40 years of its existence, Oak Ridge was used primarily to track minor planets and big rocks in the solar system, Latham said. But in the 1980s, astronomers began to use new technology to measure distant stars very carefully over long periods of time. The goal was to create standards to compare against other stars.

Around 1 a.m. on April 1, 1988, while crunching numbers for one of those stars, Latham came to the conclusion that he was looking not at a star, some 75 light years -- or 440 trillion miles -- away, but a planet 10 times the size of Jupiter.

It was the first time a planet beyond our own solar system had been discovered.

''My reaction was 'Whoa! Is this what I think it is?' " Latham said. ''My first inclination was to call my wife and wake her up, but since she's a doctor I decided she wouldn't be too happy about that."

The discovery was international news and set Oak Ridge on a course to continue surveying for distant planets for the next 27 years. As many as another 150 planets have been located since, many by observations made at Oak Ridge.

When the observatory is closed at the end of the summer, the work formerly funded by the Smithsonian at Oak Ridge will be moved to a similar Smithsonian scope in the mountains outside of Flagstaff, Ariz., Stefanik said.

The fate of the two smaller telescopes at Oak Ridge has not been determined, but the Search for Extra Terrestrial Intelligence effort will continue on the site, as will a small seismic station funded by Harvard.

Douglas Belkin can be reached at dbelkin@globe.com.