“I’ve got to hold on,” I think, in the thin, cold air. Wrapped in a winter parka, I’m shivering on the catwalk high inside the W.M. Keck Observatory, trying to comprehend what the guide is saying about the telescope mirror 25 feet below us. Consisting of 36 separate segments arranged in a hexagon, this is the largest mirror yet for optical astronomy. It’s to be tested this night to make sure the pioneering design can be controlled with computers. So far, all the tests have proven that it will produce the clearest images of our universe ever collected.
Seven hundred metric tons of steel and concrete separate the universe and this $94 million telescope. Outside the dome, the summit of Mauna Kea is just about freezing, and inside the observatory it isn’t much warmer. Even here the air is automatically cooled to keep the mirror from fogging up. Being in the observatory is a chilling experience.
In the artificial cold, the mirror hangs silently in its scaffolding, patiently awaiting Jerry Nelson to open, pivot and aim the telescope at some distant galaxy. Nelson, the astrophysicist from the University of California, Berkeley who designed the daring Keck telescope, is downstairs preparing for the night’s test. “It’s faint stars we’re after that nobody else can pursue,” he says, moving lithely about in his red checkered wool shirt, warmly confident that his gamble will payoff.
Inside the control room, Nelson phones the other observatories on Mauna Kea to ask for their readings of the outside humidity, since both of the Keck’s devices for measuring moisture in the air have recently broken. The dome won’t open tonight until the humidity level outside drops, so we sit patiently before the 20 dark computers that operate the observatory. The telescope is not visible from the control room.
While we wait, I practice mountain climbers’ breathing techniques to get sufficient oxygen into my body. A song by the group Breathe comes on the radio, which picks up Honolulu stations clearer than I can from my Makiki apartment. Being high has its advantages.
Later, we sit in the kitchen drinking fruit juice, and Nelson talks about his creation. “We’re going to discover things we have no ideas about.”
The chance for new discoveries will be even greater when the telescope now under construction next to the Keck begins searching the skies. The Keck II, identical to Keck I, will be ready in 1996. Astronomers will then be able to experiment with optical interferometry: light from both telescopes will be focused together-like looking through binoculars-to produce an image ten times clearer than with a lone telescope.
Outside, the Keck Observatory glows beneath the stars. Nelson’s words echo in the icy air: “Sometimes I actually say, ‘Wow, this is neat. I’m looking at stars no one’s ever seen before!’ ”