A giant telescope 80 feet in diameter to capture the Universe

Images 10 times sharper than the Hubble telescope
August 26, 2013

The Giant Magellan Telescope will be one of the next class of super giant earth-based telescopes that promises to revolutionize our view and understanding of the universe. It will be operational in about 10 years and located in Chile. (Credit: Steward Observatory Mirror Lab)

The Steward Observatory Mirror Lab (SOML) at the University of Arizona is spin-casting the world’s largest telescope mirror: the Giant Magellan Telescope (GMT), which will be more than 80 feet in diameter.

In comparison, the mirror of the Hubble Telescope measures 94.5 inches (just over 7.5 feet) from one edge to the other; that mirror has allowed astronomers to capture some of the most miraculous images of the universe humanity has ever seen.

SOML is unique in the world; no other facility on the planet has the combination of engineering expertise — from optical to mechanical to thermal — and the equipment to manufacture mirrors as large and sophisticated as the ones made here.

“If you want higher resolution and more light, you need to put more than one mirror together and make them work together,” says Roger Angel, PhD, University of Arizona professor of astronomy.

Today, the largest telescope in the world is the Large Binocular Telescope on Mount Graham in Arizona, with two 27-foot mirrors made in the SOML.

Seven 27-foot mirrors

The Large Binocular Telescope has worked so well that now we want to make one with seven 27-foot mirrors working all together, explains Angel. He is talking about the Giant Magellan Telescope (GMT), which will be more than 80 feet in diameter. It will be completed in about 10 years and be located on a mountain top in Chile.

“When you put seven of them together,” says Angel, “you make images which are 10 times sharper than the Hubble telescope. What makes these mirrors get the best images, you have to control the shape and everything, but you have to control their temperature, they have to be exactly the right temperature to make a good image. If it gets out of hand, you can stress it or crack it.”