Next-Gen Megascope for Astronomy Taking Shape on Chilean Mountaintop

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https://www.space.com/giant-magellan...ion-chile.html

Next-Gen Megascope for Astronomy Taking Shape on Chilean Mountaintop
By Mike Wall a day ago Science & Astronomy

The Giant Magellan Telescope should be observing the heavens by 2026.

The Chilean mountaintop where the Giant Magellan Telescope will rise,
as seen in May 2019.The Chilean mountaintop where the Giant Magellan
Telescope will rise, as seen in May 2019.(Image: © Giant Magellan
Telescope – GMTO Corporation)
An arid mountaintop in the Chilean Andes is being transformed into a
next-generation astronomy hub.

Hard-rock excavation at the Giant Magellan Telescope (GMT) site — a
patch of rocky desert 8,200 feet (2,500 meters) above sea level, about a
2-hour drive from the coastal town of La Serena — wrapped up in March.
And the project team recently selected a contractor to build the mount,
a steel structure that will house the huge telescope's mirrors and
scientific instruments.

"This is the core of the observatory," said Robert Shelton, president of
the GMTO Corp.

Report: Gallery: The Giant Magellan Telescope Envisioned in Chile

Mount construction "is the single largest procurement we will be
involved with — anywhere from $120 million to $140 million," Shelton
told Space.com.

Total costs for the project are expected to exceed $1 billion, he added.

The GMT will integrate seven primary mirrors to form a light-collecting
surface 80 feet (24.5 m) wide, giving the scope a resolving power 10
times greater than that of NASA's Hubble Space Telescope. (The scope
will also employ seven smaller secondary mirrors, which will bounce
light from the primaries down to a camera system.)

Overhead view of the Giant Magellan Telescope site in mid-March 2019.
Excavation for the pier and enclosure foundations is complete. Trenching
work for the upgraded water and electrical distribution systems can be
seen at the top of the image.

Overhead view of the Giant Magellan Telescope site in mid-March 2019.
Excavation for the pier and enclosure foundations is complete. Trenching
work for the upgraded water and electrical distribution systems can be
seen at the top of the image.

(Image: © Giant Magellan Telescope – GMTO Corporation)
The GMT will therefore be able to make groundbreaking observations in a
number of fields, project team members have said. For example, the
megascope will scan the atmospheres of nearby alien planets for possible
signs of life, help astronomers understand how the first galaxies
formed, and gather data that could shed light on mysterious dark matter
and dark energy.

Five of the primary mirrors have already been cast, at the University of
Arizona's Richard F. Caris Mirror Laboratory. One of those five is
completely done, and the other four are in various stages of processing.
(It takes a long time and a lot of exacting work to turn a raw cast
mirror into a precisely polished finished product.)

Each primary mirror, by the way, is about 27 feet (8.4 m) wide — so big
that these key pieces will have to travel to Chile by boat.

Related: Report from Chile: Giant Magellan Telescope Groundbreaking

Shelton said he expects the GMT to start observing the heavens in 2026,
with just four or five of the primary mirrors installed.

"As soon as we have the mount, the enclosure, the utilities and the
first couple of instruments, there's no reason to wait for mirrors six
and seven," Shelton said. "We'll go for that, start the engineering
studies. There will always be surprises in a project this big, so let's
get those going, work out the surprises and start doing science as soon
as we can."

The telescope should be fully up and running by 2028, he added.

The GMT team must overcome a number of technical challenges to achieve
their ambitious goals. Managing the scope's huge data haul will be
difficult, for example, and the primary mirrors' surfaces must be pretty
much perfect. (They can only be off by about 20 nanometers — roughly the
width of a single glass molecule.)

But the toughest hurdle probably involves funding, Shelton said. GMT is
a privately run project and must work hard to bring money in on
schedule, from both donors and institutional partners such as
universities (whose contributions will get them observing time and
access to project data).

"I'm confident we're going to get the funding we need, but we also need
to get it on the timeline we need," Shelton said. "And the longer you
take to build it, the more it costs."

GMT isn't the only megascope in development. Two others are scheduled to
come online in the mid-2020s as well — the Thirty Meter Telescope in
Hawaii and the Extremely Large Telescope, on another high and dry
Chilean peak.

These three scopes will have similar aims. But they won't be redundant,
Shelton said.

For example, the trio will provide coverage of both the northern and
southern skies, he pointed out. And their science instruments won't be
identical.

Accounting for bad weather and the time needed to do engineering work,
each scope will likely have about 320 observing nights per year, he
said. So, there'll be about 960 nights available annually on these
powerful instruments — nowhere near enough to satiate scientists' wants
and needs.

"The astronomy community will gobble that up," Shelton said.

Time on these scopes, which will seek to answer some of the biggest
questions in science, will be precious for decades to come, he added.

"These observatories are going to last 50 years," Shelton said.

Gallery: The Giant Magellan Telescope Envisioned in Chile
Photos: Casting Mirror No. 5 for the Giant Magellan Telescope
10 Biggest Telescopes on Earth: How They Measure Up
Mike Wall's book about the search for alien life, "Out There" (Grand
Central Publishing, 2018; illustrated by Karl Tate), is out now. Follow
him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or
Facebook.

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