BioEd Online

On a quiet Sunday morning in Hawaii, astronomer Tom Geballe had just wrapped up his graveyard shift at the giant, 8-metre Gemini telescope. He had retired to the off-site dormitory and was settling in to watch some American football when he felt the ground begin to move. Quickly, he leapt into a doorframe and waited until the earthquake passed. "It was a good shake," Geballe says. "We realized immediately that we had to go back up the mountain."

The 6.6-magnitude quake struck at shortly after 7am local time on 15 October, about 50 kilometres west of Mauna Kea, the 4,205-metre peak that's home to Gemini and about a dozen other telescopes. It was a strong earthquake, probably created by the weight of the island of Hawaii pressing down on the Earth's mantle, says Cecily Wolfe, a seismologist at the University of Hawaii, Manoa. It was so powerful that it knocked out electricity in the capital city of Honolulu some 250 kilometres west of the epicentre.

But despite the quake's size and strength, the large telescopes atop Mauna Kea seem to be mostly intact although some have been put out of action for at least a few days.

Lucky break

Assessments are still underway, but none of the major telescopes reported damage to their massive primary mirrors. "It looks like we survived without any significant damage," says Catherine Ishida, research coordinator for Japan's 8.2-metre Subaru telescope. The elevator to the telescope's control room has been knocked out of commission, but all other systems appear to be working, Ishida says.

Although the mirrors are luckily unbroken, there was some other damage. The dual 10-metre Keck telescopes and the smaller, 3.6-metre Canada-France-Hawaii telescope (CFHT) all suffered some knocks to their 'encoders', which help the telescopes to determine their exact orientation. Some systems used to move the Keck II telescope were also damaged.

The CFHT will be down until one of its encoders can be replaced, according to the telescope's director Christian Veillet, and Keck II is likely to be offline for more than a few days as well, says spokeswoman Laura Kinoshita. Still, she says, the Keck's mirrors, instruments and computer systems are in good shape: "Overall, our facility came through it remarkably OK."

People power

"The good news is that everybody's fine," adds Veillet. "Our staff is the most precious resource we have."

As for the Gemini, after racing up the mountainside around fallen boulders, Geballe and his colleague arrived to find the telescope without power. "The emergency power was on and lots of alarms were beeping," he says. "We called the engineer on our cell phone and he guided us in the process of switching over to the back-up generator." Then they returned to the dormitories for a good day's rest.

Gemini's systems mostly appear to be in good shape, and once they have all been checked out it should resume observing, probably in several days' time.

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