Work on Seventh and Final Giant Magellan Telescope Mirror Begins

The GMTO Corporation in Pasadena announced it has started the fabrication and polishing process for the seventh and last primary mirror of the Giant Magellan Telescope. This four-year endeavor will culminate in a completed light-collecting surface of 368 square meters for the international project.

The mirrors will collect more light than any other telescope in existence, allowing humanity to unlock the secrets of the Universe by providing detailed chemical analyses of celestial objects and their origin. 

Technicians at the University of Arizona’s Richard F. Caris Mirror Lab last week closed the lid on nearly 20 tons of pure optical glass inside a one-of-a-kind oven housed beneath the stands of the Arizona Wildcats Football Stadium, according to a GMTO statement. The spinning oven will heat the glass to 1,165°C – or 2,129°F – so as it melts, it is forced outward to form the mirror’s curved paraboloid surface. 

“We are in an important stage of fabrication, with much of the manufacturing happening in the United States,” Robert Shelton, President of the GMT Organization, said. 

The 39-meter-tall telescope structure is being manufactured with 2,100 tons of American steel at a newly-built manufacturing facility in Rockford, Illinois.

At 50 million times more powerful than the human eye, the telescope “will make history through its future discoveries,” said Buell Jannuzi, Principal Investigator for the fabrication of the Giant Magellan Telescope primary mirror segments, Director of Steward Observatory, and Head of the Department of Astronomy at the University of Arizona.

 “We are thrilled to be closing in on another milestone in the fabrication of the Giant Magellan Telescope,” Jannuzi said. 

The mirror measures 8.4-meters in diameter and will cool over the next three months before moving into the polishing stage. 

Once assembled, all seven mirrors will work in concert as one monolithic 25.4-meter mirror. 

Rebecca Bernstein, Chief Scientist for the Giant Magellan Telescope, said the combination of light-gathering power, efficiency, and image resolution will enable scientists to make new discoveries across all fields of astronomy. 

“We will have a unique combination of capabilities for studying planets at high spatial and spectral resolution, both of which are key to determining if a planet has a rocky composition like our Earth, if it contains liquid water, and if its atmosphere contains the right combination of molecules to indicate the presence of life,” Benstein said. 

GMTO Corporation is an international consortium of 13 research institutions representing six countries. The telescope is under construction in Chile and anticipated to be completed in the late 2020s.

For more information, visit www.giantmagellan.org.