The Giant Magellan Telescope’s 6th Mirror has Just Been Cast. One More to Go

By 2029, the Giant Magellan Telescope (GMT) in northern Chile will begin collecting its first light from the cosmos. As part of a new class of next-generation instruments known as “extremely large telescopes” (ELTs), the GMT will combine the power of sophisticated primary mirrors, flexible secondary mirrors, adaptive optics (AOs), and spectrometers to see further and with greater detail than any optical telescopes that came before.

At the heart of the telescope are seven monolithic mirror segments, each measuring 8.4 m (27.6 ft) in diameter, which will give it the resolving power of a 24.5 m (80.4 ft) primary mirror. According to recent statements from the GMT Organization (GMTO), the University of Arizona‚Äôs Richard F. Caris Mirror Lab began casting the sixth and seventh segments for the telescope’s primary mirror (which will take the next four years to complete).