Giant Magellan Telescope: New Mega-Telescope in Chilean Andes

Artist's impression of the Giant Magellan Telescope's mirror system.

Credit: Giant Magellan Telescope /GMTO Corporation

A gigantic telescope designed to help astronomers solve some of the universe's deepest mysteries will soon start taking shape atop an arid mountain in the Chilean Andes.

The Giant Magellan Telescope (GMT) completed several major external reviews earlier this year and is on target to enter the construction phase before the end of 2014, project representatives said.

If all goes according to plan, the megascope should begin observing the heavens early in the next decade.

"The group here on the project is basically anticipating that we will begin construction activities late this year," GMT director Patrick McCarthy, Carnegie Observatories, told reporters.

"We're going ahead full steam, aiming for that 2021 first light when the first few mirrors get up on the mountain, along with all the rest of the hardware."

Scientists will use the enormous telescope to probe the nature of mysterious dark energy and dark matter, find and characterise exoplanets and study how the universe's first stars and galaxies came together, GMT representatives have said.



The Giant Magellan Telescope (GMT) will be built on Chile's Las Campanas Peak, at an altitude of about 8,500 feet (2,550 meters). The site was leveled by an excavation blast in March 2012.

GMT will arrange seven 27.6-foot-wide (8.4 m) primary mirrors, the biggest single-piece astronomical mirrors ever made, into one light-collecting surface 80 feet (24 m) across.

The completed scope will have 10 times the resolving power of NASA's iconic Hubble Space Telescope, project representatives say.

The third primary mirror for the Giant Magellan Telescope (GMT) is cast in a spinning furnace at the University of Arizona's Steward Observatory Mirror Lab on Aug. 23, 2013.

Credit: Mike Wall/Space.com

The GMT design also incorporates seven smaller secondary mirrors, which will change shape to counter the blurring effects of Earth's thick atmosphere.

Each of GMT's 20-ton primary mirrors must be shaped and smoothed to near perfection. Their surfaces cannot be off by more than 20 nanometers, about the width of a single glass molecule.

Adding to the difficulty is the fact that six of the mirrors must be steeply curved, since they surround a central (symmetric) mirror.

Manufacturing and polishing the primary mirrors, activities that are done at the University of Arizona's Steward Observatory Mirror Lab, have proved to be enormously challenging, McCarthy said.

But one of the big mirrors is finished, while two others have already been cast. Casting of the fourth one is scheduled for next March.

"So we've dealt with that as our principal technical risk, and we've retired that," McCarthy said.



Fundraising is another challenge. The project's total cost is pegged at $860 million, though perhaps another $100 million will eventually be needed to cover contingencies and the cost of inflation, McCarthy said.

The money will be provided by GMT's many partners, which include educational institutions such as the University of Arizona, Harvard and the University of Chicago, private organizations like the Carnegie Institution for Science and international entities, such as the state of Sao Paulo in Brazil.

Money is now coming in "at a rate that makes us pretty confident that we'll manage to raise enough funds to keep the project on schedule, and that the schedule will be set by the engineering rather than by how fast we can raise money," McCarthy said.

The Giant Magellan Telescope's third primary mirror

The Giant Magellan Telescope's third primary mirror will be unveiled at the University of Arizona's Steward Observatory Mirror Lab on December 6, 2013.

The combined surface area of the three mirrors created to date surpasses that of any existing telescope and will help enable astronomers to peer more deeply into space than ever before once the telescope is completed.

Primary mirrors are the heart of the modern day reflecting telescope. They capture and focus photons coming from space to help construct images of the universe and collect complex spectra.

Generally, the larger the surface area of the primary mirrors, the more photons they can capture, leading to better images and improved data.

The Giant Magellan Telescope will offer the best image resolution ever seen to explore deep space.

"The Giant Magellan Telescope will be one of the most powerful tools for approaching some of society's most profound questions: where did we come from, where are we going, and are we alone in the universe?" said Patrick McCarthy, Giant Magellan Telescope Project Director.

"The technology used to design and construct the telescope is breathtaking, but the answers it may provide as to the beginnings of time itself will be staggering."

The first of a new generation of "extremely large telescopes," or "ELTs," the Giant Magellan Telescope will have a mirror array consisting of seven 27-foot- (8.4-meter-) diameter mirror segments.

The telescope is anticipated to begin operation in 2020 with four mirror segments completed, making it the largest telescope in the world.

When its final stages of construction are complete, it will have ten times the resolution of the Hubble Space Telescope.

The Giant Magellan Telescope

Plans for an enormous new telescope in Chile took a major step forward this week with a $50 million infusion from the University of Chicago to aid the observatory's construction.

The new observatory, called the Giant Magellan Telescope, is designed to detect objects 100 times fainter than those seen by the Hubble Space Telescope.

The University of Chicago funds will help cover the anticipated $700 million cost for the telescope, which astrophysicists hope will be able to collect valuable data needed to make strides in understanding dark matter and dark energy, the project's planners said.

The Giant Magellan Telescope will consist of six circular mirrors, each 28 feet (8.4 meters) across, set in a flower-petal arrangement around a seventh central mirror to make up the GMT's main mirror.

Together, the mirrors form the equivalent of a nearly 82-foot (24.5-meter) telescope. The new telescope will be built at the Las Campanas Observatory in Chile, and should take about seven years to complete.