TUCSON, Ariz. (KGUN) — Construction is underway on a next-generation optical telescope, up to 200 times more powerful than the best telescopes used today.
The Giant Magellan Telescope's seven mirrors are being made right here at the University of Arizona.
"There's no other university in the world that has a production facility like this," said Hubert "Buddy" Martin, Project Scientist for Mirror Polishing.
The production facility is the University of Arizona's Richard F. Caris Mirror Lab. It is a hidden gem at the university, tucked underneath the east side of Arizona Stadium.
Despite being hidden away, the lab is world-renowned for its cutting-edge development of optical telescope mirrors.
"All of these 8.4 meter mirrors are the biggest mirrors that have ever been made," explained Martin.
Right now they're making the seven mirrors for the Giant Magellan Telescope which will be located in Chile.
But to better understand what they're doing now, you have to go back to the beginning—the early 1980s.
"Roger Angel and John Hill and some of the colleagues developed a method of lightweight mirrors," said Martin.
In 1985, Dr. Angel—with financial support from the U of A, the U.S. Air Force and the National Science Foundation—began the mirror lab under Arizona Stadium.
"Developed this enterprise to make mirrors that were better than anything else that was available and now they've gone into a lot of telescopes that the U of A is a partner in," Martin said.
One of their first mirrors can still be found at the Vatican Observatory, the Pope's Telescope, on Mt. Graham near Safford, Ariz. The 1.8-meter mirror happens to be the first mirror Buddy Martin worked on.
"It was the first one made by spin casting," said Martin. "We rotate the furnace while the glass is melting and the centrifugal force gives it naturally the parabolic surface you need for a telescope."
From there, the mirror lab used spin casting to create even larger mirrors.
"The challenge is if you make it bigger it doesn't want to hold its shape accurately," Martin explained. "A telescope mirror has to hold its shape to something like a millionth of an inch."
The mirror lab has solved that issue, now casting 8.4-meter mirrors. That is nearly 28 feet across.
They have now cast all seven mirrors for the Giant Magellan. The six outer mirrors have a unique saddle shape.
"That's because we're putting seven of them together to work like a single primary mirror that's 25 meters, or 80 feet, in diameter," Martin said.
It takes about 4 years to make each of the seven mirrors for the Giant Magellan Telescope.
"Fortunately we can work on three or four at a time," said Martin. "We have four different stations in the lab. So, we can produce mirrors more rapidly than every four years. But each one takes about four years."
Martin is in charge of polishing each mirror. They start with this rough grinding.
"We'll go to a different kind of operation, a polishing operation, to get it ultimately to the accuracy of a millionth of an inch," Martin said.
Right now they are celebrating a milestone at the mirror lab. For the first time, they are testing one of the completed 8.4-meter mirrors on the support cells, which will hold the mirror in the Giant Magellan Telescope.
"You have to have a very complex support system for one of these mirrors," said Martin.
In order for the mirror to hold its shape while pointing toward the stars, the support system includes 165 actuators to push and pull the back of the 12.5-ton mirror.
In the coming months, they'll move the mirror and support system under the mirror lab's test tower, to measure the mirror for accuracy with lasers.
Right now, the completed mirrors have a protective blue coating on the surface.
They aren't actually mirrors yet. The reflective coating, only 4 millionths of an inch thick, is added on site.
"This piece of glass that costs many millions of dollars and takes years to make, the whole purpose of it is to hold that layer of aluminum in the right shape," Martin said. It's the aluminum that does all the work."
The seven mirrors will be shipped to Chile later this decade. The Giant Magellan Telescope is supposed to be operational by the early 2030s.
"This is a bigger telescope than anything that exists and it's going to do things that have never been done before," said Martin.
It could perhaps even find an illusive exoplanet, with proof of life elsewhere in the universe.
Each of the 8.4-meter mirrors cost about $30 million. The Giant Magellan budget is more than $2.5 billion.
The Richard F. Caris Mirror Lab is named for a generous donor.
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Pat Parris is an anchor and reporter for KGUN 9. He is a graduate of Sabino High School where he was the 1982 high school state track champion in the 800 meters. While in high school and college, he worked part-time in the KGUN 9 newsroom. Share your story ideas and important issues with Pat by emailing pat.parris@kgun9.com or by connecting on Facebook, Twitter, and Instagram.