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GMTO/Ricardo Alcayaga

GMTO

GMTO

It has been a long road for planners of the Giant Magellan Telescope, which will become the world's largest telescope—if it's completed on schedule. Casting of the first of seven mirrors, each formed from about 20 tons of borosilicate glass made from Florida sand, began way back in 2005. The project seems to finally be closing in on first light as the team amps up fundraising and construction efforts.

The organizers of the telescope are gearing up for fundraising needed to bring the project to completion and have hired a new president with significant executive experience: Robert N. Shelton, a former president of the University of Arizona and provost and executive vice chancellor of the University of North Carolina at Chapel Hill. "Anyone who has been a president and a provost understands the importance of fundraising," Shelton told Ars in an interview.

In the last 15 years or so, the project to build a 24.5-meter telescope in Chile's Atacama desert has raised slightly more than half of the project's $1.05 billion cost. The telescope would be about two-and-a-half times larger than any existing optical telescope. Raising the remainder will not be easy for a telescope, Shelton acknowledged. "For grateful alumni or hospital patients that’s a smaller number in terms of a fundraising campaign," he said. "But if you’re an observatory, it’s a little more challenging."

In the meantime, the group has continued to press ahead with construction at the site in the high desert. In late 2015, bulldozers began leveling a road to the site at 2,516 meters (8,255 feet), and during the past year, three buildings have been constructed that will provide housing for workers and eventually,astronomers. By the end of this year, Shelton said, excavation will begin to build a foundation for the massive telescope itself, and the organization will issue "requests for proposals" for mirror mounts that will support each of the 8.4-meter mirrors.

The current timeline calls for completing construction of a partial four-mirror version of the telescope (which will have seven mirrors when completed) in 2023. Four of the mirrors have been cast and are in various states of polishing. But the overall timeline remains aspirational and dependent upon funding. A decade ago, the group had intended to finish the telescope as early as 2016.

Time matters because two other projects are also in various stages of building a super-large optical telescope—The Thirty Meter Telescope led by California institutions and backed by the Gordon and Betty Moore Foundation, and a European telescope consortium with an even more ambitious 39-meter instrument. The Thirty Meter Telescope project has run into controversy as some native Hawaiians oppose the instrument's construction atop Mauna Kea on Hawaii’s Big Island. The European project also faces significant technical problems associated with assembling such a large instrument.

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