[meteorite-list] Mirror Casting Event for the Giant Magellan Telescope

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 9 Jan 2012 13:03:17 -0800 (PST)
Message-ID: <201201092103.q09L3HIV028835_at_zagami.jpl.nasa.gov>

FOR IMMEDIATE RELEASE
FROM THE UNIVERSITY OF ARIZONA

Jan. 9, 2012

Contact information follows this news release.

Mirror Casting Event for the Giant Magellan Telescope

On Jan. 14, the second 8.4-meter (27.6 ft) diameter mirror for the Giant
Magellan Telescope, or GMT, will be cast inside a rotating furnace at the
University of Arizona's Steward Observatory Mirror Lab underneath the
campus football stadium. The mirror lab will host a special event to
highlight this milestone in the creation of the optics for the Giant
Magellan Telescope.

Members of the media are invited to visit the mirror lab on Jan. 14
between 9-11 a.m. MST to see the liquid glass as it is spun cast in a
rotating oven at a temperature of 1170 degrees C (2140 F). This casting
marks another major step in the construction of the Giant Magellan
Telescope. There will be opportunities to interview leading scientists and
engineers involved in the project.

The GMT features an innovative design utilizing seven mirrors, each 8.4
meters in diameter, arranged as segments of a single mirror 24.5 meters
(80 feet) in diameter, to bring starlight to a common focus via a set of
adaptive secondary mirrors configured in a similar seven-fold pattern.

"In this design the outer six mirrors are off-axis paraboloids and
represent the greatest optics challenge ever undertaken in astronomical
optics by a large factor," said Roger Angel, director of the Steward
Observatory Mirror Lab, or SOML.

The GMT will allow astronomers to answer some of the most pressing
questions about the cosmos including the detection, imaging and
characterization of planets orbiting other stars, the nature of dark
matter and dark energy, the physics of black holes, and how stars and
galaxies evolved during the earliest phases of the universe.

"The GMT will allow astronomers to observe for the first time the first
stars formed
after the Big Bang," said Steve Finkelstein, Hubble Fellow at The
University of Texas at Austin. "I cannot wait to make these observations."

"Astronomical discovery has always been paced by the power of available
telescopes and imaging technology," said Peter Strittmatter,
director of Steward Observatory. "The GMT allows another major step
forward in both sensitivity and image sharpness. In fact the GMT will be
able to acquire
images 10 times sharper than the Hubble Space Telescope and will provide a
powerful complement not only to NASA's 6.5-meter James Webb Space
Telescope, or JWST, but also to the Atacama Large Millimeter Array, or
ALMA, and the Large Synoptic Survey Telescope, or LSST, both located in
the southern hemisphere."

Patrick McCarthy, GMT project director, added, "This second GMT casting is
going forward now because the primary optics are on the critical path for
the project, and because the polishing of the first off-axis 8.4-meter GMT
mirror is very close to completion, with an optical surface accuracy
within about 25 nanometers, or about one-thousandth the thickness of a
human hair."

Like other mirrors produced by the SOML, the GMT mirrors are designed to
be spun cast, 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.

Some 21 tons of borosilicate glass, made by the Ohara Corporation, flow
into a pre-assembled mold to create a lightweight honeycomb glass
structure that is very stiff and quickly adjusts to changes in nighttime
air temperature, each resulting in sharper images. The mirror lab has
already produced the world's four largest astronomical mirrors, each 8.4
meters in diameter. Two are in operation in the Large Binocular Telescope,
or LBT - currently the largest telescope in the world; one is for the LSST,
and the fourth is the first off-axis mirror for GMT. The UA's Mirror Lab
has
also produced five 6.5-meter mirrors, two of which are in the twin
Magellan telescopes at Las Campanas Observatory in Chile.

"The novel technology developed at the mirror lab is creating a whole new
generation of large telescopes with unsurpassed image sharpness and light
collecting power," said Wendy Freedman, director of the Carnegie
Observatories and chair of the GMTO Board. "The SOML mirrors in the twin
Magellan Telescopes at our Las Campanas Observatory site are performing
superbly and led to our adoption of this technology for the GMT."

The GMT is set to begin science operations in 2020 at the Las Campanas
Observatory, exploiting the clear dark skies of the Atacama Desert in
northern Chile.

"With funding commitments in hand for close to half of
the $700 million required to complete the project, with one mirror
essentially finished and the second about to be cast, and with the planned
groundbreaking at Las Campanas in February of this year, the project is on
track to meet this schedule goal," said Matthew Colless, Director of the
Australian Astronomical Observatory.

"The giant mirrors being spun cast for the GMT at the Steward Observatory
Mirror Lab are like the sails of the great ships of exploration ca. 1500,
except here the discoveries are not lands across the ocean, but rather the
nature of whole new worlds and island universes, spanning all of space and
time," said Joaquin Ruiz, dean of the College of Science, University of
Arizona. "We are proud to participate in such an exciting
international scientific project as the GMT."

The event is supported by the University of Arizona's Steward Observatory
and College of Science and by the GMTO Corp., a nonprofit entity with
project offices based in Pasadena, Calif. The GMTO manages the GMT Project
on behalf of its international partners, namely 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:

Roger Angel, director, SOML (rangel at as.arizona.edu; 520-621-6541)

Patrick McCarthy, director, GMTO (pmccarthy at gmto.org; 626-304-0222)

Wendy Freedman, chair, Board of Directors, GMTO
(wendy at obs.carnegiescience.edu; 626-304-0204)

Peter Strittmatter, director, Steward Observatory
(pstrittmatter at email.arizona.edu; 520-621-6524)

Peter Wehinger, staff astronomer and director of development, Steward
Observatory (wehinger at email.arizona.edu; 520-621-7662)

Cathi Duncan, coordinator (cduncan at as.arizona.edu; 520-626-8792)


# # #

LINKS:

For more information about the GMT, see www.gmto.org.

For images, see http://www.gmto.org/forpress.html.

The University of Arizona Steward Observatory Mirror Lab:
http://mirrorlab.as.arizona.edu
Received on Mon 09 Jan 2012 04:03:17 PM PST