The Richard F. Caris Mirror Lab at the University of Arizona builds mirrors for telescopes. Not backyard telescopes, but gigantic, mountain-top telescopes that can see into the deepest regions of outer space. Am I getting too dramatic? It was a very interesting visit! The tour was actually about 60% lecture and 40% tour. Our guides have worked at the lab for many years and did a wonderful job explaining the manufacturing process.
It takes about 2 years to produce one mirror. Basically, a mold is built, a furnace is constructed around the mold, the glass mirror is cast, and is then refined and polished.
The photo below shows the furnace floor. A honeycomb support structure is built on the floor, and then the furnace is constructed around the mold. The lab rebuilds (and takes apart) the furnace each time they produce a mirror.
Do you see that big, round, white slab under the yellow railings in the photo below? That’s a mirror! A TWENTY-SEVEN FOOT wide mirror! The part we can see with the honeycomb structure is the back, and the mirrored surface will be on the opposite side.
After casting, the mirror is tested, refined, tested, refined…you get the point. Our guides told us that nothing used in the manufacturing process is bought off the shelf, except for their diamonds. Yes! They use diamonds for shaping and smoothing the mirror surface. (At this point, the mirror is just glass, without the reflective coating.) The testing and refining process will adjust the mirror surface to be within nanometers of perfection. This photo shows the polishing machine—it’s that large round robot with all the tubes on the disc.
The mirror we saw (cast in September 2015) is mirror number 4 of the Giant Magellan Telescope . The Giant Magellan Telescope is a (privately funded) billion dollar project that will be constructed in Chile in the Andes Mountains. Imagine how they’re going to transport seven 27-foot tall mirrors to a mountain top! Here’s a model of the telescope:
And here’s a photo of a drawing that includes a human for scale:
What!? Amazing! The Giant Magellan Telescope will be 10-times more powerful than the Hubble, seeing further in distance and time, and it will be able to do that from Earth!