Palomar Observatory, an array of vanilla-colored domes adorning a pine-shrouded mountaintop 150 miles southeast of Los Angeles, is nearly 40 years old--old enough by the headlong standards of high technology to qualify as an engineering antique--yet it remains a vital center of scientific research. I visited Palomar recently to sit up with the astronomers through a night's observing run.
I arrived at sunset and drove onto the observatory grounds, pausing to enjoy the sight of the dome that houses Palomar's centerpiece, the legendary Hale telescope. A monument to aesthetics as well as to science, the dome, 13 stories high, is utterly graceful in its proportions: This is how an observatory ought to look. The dome was warmed to amber by the last light of the setting sun. Its huge, 125-ton shutters had been drawn back to let out the heat of the day gone by. Inside loomed the telescope's battleship-gray skeleton tube, yawning wide enough to swallow a two-story bungalow.
The Hale telescope, with its 200-inch-diameter light-gathering mirror, is arguably the world's largest fully functional telescope. (The Soviets' 236-inch instrument, at Zelunchukskaya in the Caucasus Mountains, has problems with its massive mounting, and its use is hampered by foul weather.) The smaller telescopes on Mt. Palomar, including a 48-inch Schmidt telescope that takes wide-angle photographs embracing 36 square degrees of the night sky (the full moon is only half a degree wide), are also much in demand. Astronomers vie for the opportunity to work beneath Palomar's steady if slightly light-polluted skies. ("Steady," to astronomers, means having little of the air turbulence that makes stars appear to twinkle.)
In "the Monastery," where astronomers are quartered during their stay on the mountain, I had dinner and caught up on news of the latest comets and exploding stars from telegrams and reports tacked on the bulletin boards. The Monastery--so named in the days when nearly all astronomers were male--sports the heavy leather armchairs, book-lined walls and Spartan sleeping quarters of an exclusive men's club. But the books are back issues of the Astrophysical Journal and Sky & Telescope magazine, the bedroom windows are equipped with heavy, black shades to block out sunlight for the observers who work all night and sleep by day, and, nowadays, a growing minority of the scientists who do their research here are women.
Observing time is an astronomer's most valuable resource, and pilgrims to Palomar come prepared to wring every hour's worth of use out of the telescopes. A typical observing run lasts only a few nights, any of which may be lost to clouds, turbulent air or equipment failure. "I enjoy observing," says Wallace Sargent, a veteran Caltech astronomer who has logged hundreds of hours at Palomar, "but it makes me nervous. I find it difficult to go to sleep in the morning. I'm worried that some screw-up might occur the next night."
Astronomers are among the last surviving generalists in an age of scientific specialization. They do their own observing, analyze their own data and, often, apply the results to theories of their own devising. But while this astronomical tradition survives, another has long since died: Astronomers today seldom look through telescopes. The human eye has been replaced by photographic plates and electronic sensors, leaving observers bereft of all but a few brief, almost voyeuristic peeks at celestial wonders like the rings of Saturn or the diamond glitter of the Hercules star cluster--sights that can leave them grinning as excitedly as tourists stepping down from their turn at the eyepiece of the public telescope at Griffith Observatory.
Mostly, as Sargent says, observing is hard work. On the night of my visit to Palomar, I found Sargent in the darkroom of the dome that houses the Schmidt telescope, wrestling with the massive 14x14-inch photographic plates he would be exposing that night. Sargent explained that the observatory was embarking on a five-year project to photograph the entire sky visible from the Northern Hemisphere. The first such "sky survey" was completed at Palomar 30 years ago, and its prints have served as standard references for observatories all over the world ever since. Thanks to today's more sensitive photographic emulsions, the new plates will record stars that are six times fainter than those on the old survey. And the Schmidt telescope has been fitted with a new $378,000 corrector lens that will make more accurate photographs, enabling scientists to pinpoint the locations of the stars and galaxies with new-found precision. This is important, Sargent noted, because "the stars have moved" during the past three decades, crawling across the sky as they pursue their various orbits in the grand wheeling of the Milky Way galaxy.