[meteorite-list] Giant Magellan Telescope Poised to Enter Construction Phase

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 24 Feb 2014 14:07:53 -0800 (PST)
Message-ID: <201402242207.s1OM7rxe022527_at_zagami.jpl.nasa.gov>

http://uanews.org/story/giant-magellan-telescope-poised-to-enter-construction-phase

Giant Magellan Telescope Poised to Enter Construction Phase
University of Arizona News Release
February 20, 2014

Featuring the world's most advanced mirror design - developed at the UA
- the Giant Magellan Telescope has cleared its design phase and now heads
in to production.

[Image]
The Giant Magellan Telescope is slated to begin operations atop a mountain
in Chile's Atacama Desert in 2020.
 
The Giant Magellan Telescope project has successfully passed two major
reviews, completing its detailed design phase and positioning the project
to enter the construction phase. Taking advantage of the world's most
advanced mirrors - designed and built at the University of Arizona -
the 25-meter telescope will have more than six times the light-gathering
area of the largest telescopes today and 10 times the resolution of the
Hubble Space Telescope.

Scientists will use the GMT to explore distant and potentially habitable
planets around other stars, to explore the Universe in the first billion
years after the big bang, and to probe the mysteries of dark matter, dark
energy and massive black holes. It will be located at the Las Campanas
Observatory in Chile, atop a remote mountain peak in the Chilean Andes.

During a weeklong review in mid-January, an international panel of experts
examined the design of the giant telescope, including its complex optical
systems and precision scientific instruments. This panel was made up of
experts involved in building telescopes around the world. The panel concluded
the project meets the technical readiness required to proceed to construction.
Immediately following the design review, a team of construction experts
signed off on the project's cost estimate and management plan.

Richard Kurz, former Project Manager for the Atacama Large Millimeter/submillimeter
Array and chair of the external panel that reviewed the GMT project noted
that the panel enthusiastically recommended that the GMT project "proceed
as rapidly as possible to construction." ALMA, which stands for Atacama
Large Millimeter/submillimeter Array, is an array of 66 radio telescopes
located in the dry and cloudless Atacama Desert in Chile.

Wendy Freedman, chair of the GMT Organization's Board of Directors and
Director of the Carnegie Observatories, said the reviews were critical
milestones required by the GMTO board to proceed with the construction
phase.

"Along with the successful casting of the first three 8.4-meter primary
mirrors and the leveling of the mountaintop in Chile, each step brings
us closer to construction," Friedman said.

As in most telescopes, the primary mirror is the heart of the telescope
and its properties dictate much of the telescope design. The UA's Steward
Observatory Mirror Lab developed a unique fabrication process resulting
in a lightweight honeycomb glass structure. Not only are these mirrors
the largest ever made - and light enough to float in water - but they
also are very stiff and quickly adjust to changes in nighttime air temperature,
all of which results in sharper images. GMT's third mirror was unveiled
just this past December.

Like other mirrors produced by the Mirror Lab, the GMT mirrors are fabricated
in a process called spin casting, thereby achieving the basic front surface
in the shape of a paraboloid. A paraboloid is the shape taken on by water
in a bucket when the bucket is spun around its axis; the water rises up
the walls of the bucket while a depression forms in the center.

In the case of the GMT, however, six mirrors will be arranged around a
seventh in the center, in a design called off-axis, thus serving as off-axis
segments of one giant mirror. This design requires the shape of the outer
mirrors to be asymmetric in profile. Picture the spinning bucket of water
again, but with the depression forming off to one side this time.

Because of their off-axis design and asymmetrical shape, these mirrors
are more challenging to polish, and to measure, than any telescope mirror
made before. The mirror surface must match the ideal off-axis shape to
an accuracy of 25 nanometers, or one-millionth of an inch. The GMT project
recognized the need to demonstrate this capability as early as possible.
The first off-axis mirror was completed in October 2012.

"Finishing the first GMT mirror is a huge milestone for the Mirror Lab,"
said Buddy Martin, a project scientist at the Mirror Lab and for the GMT,
and an associate research scientist in the UA College of Optical Sciences.
"This project builds on all the technology we've developed over 25 years
for many telescopes, but required new methods and equipment that extend
the state of the art in several ways. We now have all the technology in
place to make the rest of the GMT mirrors."

Measuring 360 square meters, or about 3,900 square feet, the GMT's seven
mirrors combine to form an area just a bit smaller than a basketball court.

"This is an exciting time for space sciences at the UA as we look forward
to the completion of GMT and its ability to enable exploration of Earth-type
planets around nearby stars to the most distant galaxies," said Buell
Jannuzi, head of the UA Department of Astronomy and Steward Observatory.
"Being part of what will be the world's leading ground-based telescope
will continue the UA's leadership in astronomy and astrophysics in the
coming decades."

Board members representing the partner research institutions that make
up the GMT consortium will meet this summer to review the construction
plan.

Mirror production at the Mirror Lab is well underway with three of the
off-axis mirrors cast and in various stages of grinding and polishing,
and the center mirror expected to be cast in early 2015. The GMT will
become operational and begin collecting data in 2020 will begin in 2020.

GMTO manages the GMT project on behalf of its international partners:
Astronomy Australia Ltd., The Australian National University, the Carnegie
Institution for Science, Harvard University, the Korea Astronomy and Space
Science Institute, the Smithsonian Institution, Texas A&M University,
the University of Arizona, the University of Chicago, and the University
of Texas at Austin.

Contacts

Cathi Duncan, Community Relations, UA Steward Observatory
cduncanf at email.arizona.edu, 520-626-8792

Davin Malasarn, Director of External Affairs, GMTO
dmalasarn at gmto.org, 626-204-0529

Michael Long, Vice President, GMTO
mlong at gmto.org, 626-204-0555

Wendy Freedman, Chair GMT Board of Directors
wfreedman at obs.carnegiescience.edu, 626-304-0204

Patrick McCarthy, Director, GMTO
pmccarthy at gmto.org, 626-204-0501
Received on Mon 24 Feb 2014 05:07:53 PM PST