Giant Telescope Mirror for Future Observatory to Be Cast Saturday

The Giant Magellan Telescope: Artist's View
An artist's illustration of the completed Giant Magellan Telescope atop Las Campanas Peak in Chile's Atacama Desert. The 80-foot (24.5-meter) telescope will consist of seven primary mirrors and feature an advanced adaptive optics system. It will be one of the largest on Earth when it's up and running in 2020.
(Image credit: Giant Magellan Telescope - GMTO Corporation)

An enormous mirror will be cast inside a scorching-hot furnace Saturday (Aug. 24), marking a key milestone in the development of a future telescope that will collect more light than any instrument built to date.

The Giant Magellan Telescope mirror, the third of the seven primary mirrors planned for the observatory, will be 27 feet (8.4 meters) across and weigh 20 tons when complete. It will be forged from chunks of borosilicate glass subjected to temperatures of 2,140 degrees Fahrenheit (1,170 degrees Celsius) inside a rotating furnace Saturday at the University of Arizona's Steward Observatory Mirror Lab in Tucson.

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Mike Wall
Space.com Senior Writer
Michael was a science writer for the Idaho National Laboratory and has been an intern at Wired.com, The Salinas Californian newspaper, and the SLAC National Accelerator Laboratory. He has also worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz.