Looking Sharp at Mt. Wilson
After decades of decline fueled in part by city lights growing ever brighter, the Mt. Wilson Observatory was lauded Saturday for re-emerging at the forefront of astronomical research.
Several universities have chosen the site in the San Gabriel Mountains as a place to build more powerful telescopes despite its proximity to Los Angeles.
“We are now getting the sharpest telescope images ever obtained in the history of astronomy,” Robert Jastrow, director of the Mt. Wilson Institute, said Saturday as scientists and benefactors gathered to celebrate the birthday of the famed 100-inch Hooker telescope.
It has been 80 years since the steel tube of World War I battleship rivets and champagne-glass lenses first opened its eye to the universe atop Mt. Wilson.
Since then, the telescope has answered some perplexing questions about the cosmos.
Through its lenses, Edwin Hubble discovered that the distant blurs in the night sky were other galaxies, containing hundreds of billions of stars like our sun. He found evidence of an expanding universe and the big bang.
The telescope reigned as the world’s finest for three decades, but fell on hard times in the face of new technology. It was closed in 1985.
During Saturday’s celebration, guests were allowed a view through an improved Hooker lens, which has been in operation for two years. “It’s like strolling down memory lane,” said one astronomer, walking about the grounds where he worked 30 years ago.
Set on a chamise and pine slope high above the San Gabriel Valley, the site is regaining its dominance as a place to view the stars.
Georgia State University picked the mountain as the place to build an array of seven telescopes, called an interferometer, that should combine the light from each lens to produce the sharpest image ever obtained, said Harvard University astronomer Sallie Baliunas.
“This will be the most powerful telescope in the world,” Baliunas said. Equivalent to what would be a 1,000-foot telescope, it will be capable of detecting a footprint on the moon or a nickel 10,000 miles away, she said.
The $15-million project, directed by astronomer Harold McAllister, is expected to be completed in 1999.
Also under construction is the world’s biggest heat-seeking interferometer, which will be able to sense what’s going on under a young star’s shroud of gas and dust, Baliunas said.
Two years ago, the Hooker telescope was computerized and refitted with adaptive lenses that give it the sharpest images anywhere. Baliunas is using it to research sunspot cycles on other stars, hoping her findings will shed some light on how our sun affects changes of life and climate on Earth.
The Mt. Wilson observatory ranks with viewing sites in Arizona, Chile and Hawaii because of a quality called “seeing”--a steady unblurred sight of the cosmos. The “seeing” here is unmatched due to a high pressure ceiling around the mountains below the observatory that drives smooth cool sea air over the telescopes.
Whereas Hawaii’s niche is the ability to detect faint nebuli, the Mt. Wilson observatory can sense fine detail.
“It’s something money can’t buy,” Baliunas said. “You can’t buy good seeing.”
Scientists have long considered the air of the San Gabriels special, in part because the high-pressure ceiling traps the haze below. When a team of astronomers traversed the rugged Wilson trail in 1889 to scope out the site for an observatory, they called it the finest view of the sky they had ever seen.
Huddled miserably around a campfire on the snow-covered slopes, one scientist on that first expedition predicted the future as he spoke to a reporter from the Pasadena Union. “Here the bandits made their rendezvous and formulated their plans to make incursions into the peaceful valley below,” he said. “But a great change has come and here the sentinels of science will stand and watch the procession of stars as they pass.”
George Hale founded the observatory on Mt. Wilson in 1904. A 60-inch reflector telescope came in 1908, followed by the 100-inch lens in 1917.
Building materials for the 500-ton dome had to be trucked in on a treacherous road. Scientists usually spent two weeks at a time in a primitive stucco building called the monastery.
Female scientists were not allowed to stay in the monastery until the 1960s. Either they stayed in a “cottage” without heat or a bathroom, or they made the journey every day.
“There was a real denial that women were working [in astronomy],” Baliunas said.
Between 1906 and 1908, Hale discovered that sunspots were intense magnetic fields that were darker because they had a lower temperature than surrounding areas of the sun’s surface.
Hubble came in the 1920s. He recognized that the faint smudges in the sky called nebuli were in fact distant galaxies. Observing that these galaxies were moving away from each other, he determined that the universe was expanding.
Hubble’s theory, combined with Einstein’s theory of relativity, concluded that the universe was created at a specific point in time, later called the big bang.
He also determined that the universe was 15 billion years old, three times as old as Earth or the sun. This opened speculation that if life existed on other planets, it might be billions of years older, and possibly more advanced.
Over the years, bigger and better telescopes were developed, including a 200-inch one built on Palomar Mountain in San Diego County in 1948.
“The observatory was essentially mothballed until we figured out this market niche that we could fulfill uniquely,” Jastrow said.
