It was an offer physics professor Gary Chanan couldn’t refuse: a
chance to participate in the University of California’s effort to build
the world’s largest telescopes.
Chanan joined UC Irvine in 1985 to
work on the twin 10-meter telescopes at the W.M. Keck Observatory in
Hawaii — a joint venture by UC and the California Institute of
Technology. Before long, he got a call from one of his former
professors, UC Santa Cruz astronomer Jerry Nelson, who developed the
telescopes’ revolutionary technology.
“Gary, how would you like a problem to work on?” Nelson asked.
Both Keck telescopes have a primary mirror with 36 hexagonal segments designed by Nelson, each 6 feet wide and weighing 800 pounds.
“They fit together like the tiles on your bathroom floor,” Chanan says. “The challenge Nelson had was matching them up so they’re like a continuous piece of glass. You have to align them to within 1/1,000 the thickness of a human hair.”
Chanan devised a highly calibrated optical “phasing” system that utilizes a camera with a “fly’s eye” lens, and the Keck telescopes came online in 1993 and 1996, giving stargazers unprecedented close-ups of the universe from Earth’s surface.
Now he’s helping out on an even more ambitious endeavor: the massive Thirty Meter Telescope, for which Chanan will adapt the alignment protocol he developed for the Keck twins.
“Thanks to the tools being created by Gary, the TMT is expected to deliver superb image quality,” Nelson says. “Gary is creative, patient and diligent. He’s respected worldwide and his advice is sought for most other major telescope projects, both on the ground and in space.”
“In a way, it’s just freshman physics,” says Chanan with characteristic modesty, “but fortunately, I teach freshman physics.
“The circle rippling outward when you throw a pebble in a lake is called a ‘wave front.’ To get good imaging in a telescope, the wave front of light reflected by the segments of mirror must be perfectly smooth. If you don’t assemble and calibrate it just right, you’ll see the steps between misaligned segments, and the image will be messed up. We look at interference patterns from neighboring segments, but we do it very carefully, in a way that lets us see and diagnose extremely subtle effects of misalignment.”
A chemist’s son who grew up tinkering in his father’s lab, Chanan developed a fascination with astronomy and earned a doctorate in astrophysics from UC Berkeley in 1978. “I started out looking through telescopes but somehow became more interested in looking at them and making them work better,” he says.
Besides fine-tuning telescopes, Chanan is an accomplished musician. He took up the violin as a youth and now plays the viola in the UCI Symphony Orchestra, as well as for musicals and other arts productions. “I play an instrument that’s in short supply, so I have a lot of opportunities to perform,” he says.
Though much of Chanan’s research is conducted on campus, he’s spent countless hours building, installing and maintaining the alignment equipment at the Keck Observatory, perched on the summit of Mauna Kea, an inactive volcano on Hawaii’s Big Island.
“In the ’90s, I probably traveled to Hawaii 60 or 70 times — not a bad gig,” he says. “But when you work at an altitude of 14,000 feet, where the oxygen level is low, you’re prone to stupid mistakes if you’re not careful.”
The Thirty Meter Telescope, a collaboration among UC, Caltech, Canada and several other international partners, also will be located at Mauna Kea, because atmospheric conditions are ideal and light pollution minimal.
“It will see its first stars in 2018,” Chanan says of the TMT. “When you build a larger telescope, you not only see fainter objects but can resolve finer details. We should be able to view planets circling around other solar systems. By then, I’ll be 70. I’d like to be part of that.”