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Planned Telescope Will Surpass Hubble in Power, Sharpness

Giving News

By Joel Barna

The University of Texas at Austin is one of nine partners in the multinational consortium planning to build the Giant Magellan Telescope (GMT), which will have the capability to study the earliest stars and galaxies and could help unlock scientific secrets that are beyond the reach of today’s telescopes.

GMT’s site, primary mirror, and adaptive optics will allow it to produce images up to 10 times sharper than those from the Hubble Space Telescope, an extraordinary advance in power for scientific discovery. And the telescope will employ new spectrographs with very wide coverage in the optical and infrared parts of the spectrum. GMT’s light-gathering power will dwarf that of today’s largest telescopes, and its spectrographs will allow for detailed analysis of the ancient light it will capture.

With a primary mirror composed of seven separate segments, the Giant Magellan Telescope's primary mirror will produce images up to 10 times sharper than those from the Hubble Space Telescope.

With a primary mirror composed of seven separate segments, the Giant Magellan Telescope will produce images up to 10 times sharper than those from the Hubble Space Telescope.

Planned for completion on a mountaintop in Chile in 2018, GMT will have a primary mirror measuring 24.5 meters (80.3 feet) in diameter. By comparison, the maximum diameter of the Hobby-Eberly Telescope at the University’s McDonald Observatory is 9.2 meters (30.2 feet) and today’s largest telescopes have primary mirrors that are 10 meters (32.8 feet) in diameter. The Hubble Space Telescope has a 2.4-meter primary mirror.

“The aperture of a telescope determines its light-gathering power,” says McDonald Observatory director David Lambert. “The bigger the telescope, the more light it can gather. We need a next-generation telescope to see distant, dim objects from the earliest universe. GMT will not only be extremely large — its design and instrumentation will give it exciting capabilities to move astronomy forward in the 21st century.”

With a projected cost of $680 million for construction and instruments, GMT will be built at Chile’s Las Campanas Observatory, an already-developed site with a dry climate, dark skies, and extremely smooth airflow. The telescope’s primary mirror will be composed of seven separate 8.4-meter circular segments on a single mount. The secondary mirror, which will focus light from the primary mirror and feed it to the telescope’s electronic instruments, will utilize an innovative adaptive optics system that can effectively cancel out distortions from our atmosphere.

Astronomers will use GMT to study in unprecedented detail how stars and their planetary systems form. It will have the capability to image planets directly and to study the gases making up their atmospheres, a crucial element in discovering Earth-like planets elsewhere in the Milky Way. GMT will also be large enough to enable detailed studies of individual stars in nearby galaxies. In addition, GMT will provide new capability for studying the formation and evolution of black holes, along with the formation of the first stars and galaxies and the evolution of large-scale structure in the universe. And GMT will enable new ways to study dark matter and dark energy, the two entities that make up most of the universe.

GMT will be built on a mountaintop at Chile’s Las Campanas Observatory, an already-developed site with a dry climate, dark skies, and extremely smooth airflow.

GMT will be built on a mountaintop at Chile’s Las Campanas Observatory, an already-developed site with a dry climate, dark skies, and extremely smooth airflow.

The nine founding partners in GMT are (in the United States) the Carnegie Institution for Science, Harvard University, the Smithsonian Institution, Texas A&M University, the University of Arizona, and UT Austin; (in Australia) the Australian National University and Astronomy Australia Limited; and (in Korea) the Korea Astronomy and Space Science Institute. Philanthropic support is being sought to help cover UT Austin’s estimated $70 million share of the project’s total cost.

Besides funding, the University will contribute its expertise in designing and building large telescopes and high-resolution spectrographs. Two UT faculty members have recently applied to the GMT Corporation in a competition for funds to support preliminary design of spectrographs that would become permanent parts of GMT. One is for optical light and one is for infrared light.

Phillip MacQueen, a senior research scientist at McDonald Observatory, is leading the effort to design QSpec, a very large high-resolution spectrograph for studying visual wavelengths. If developed, it will play a lead role in GMT’s studies of planets around other stars, along with the formation of chemical elements in stars and the chemical evolution of our galaxy. It also will allow exploration of the early universe using very distant galaxies and objects called quasars.

Dan Jaffe, a professor of astronomy, applied for funds to develop a high-resolution spectrograph called GMTNIRS, designed to analyze light in the near-infrared part of the spectrum. If developed, GMTNIRS will allow examination of the molecules found in disks around young stars — water in particular — and will be involved in the direct detection of planets and their atmospheres. Jaffe is working on GMTNIRS with colleagues in Korea.

Learn more about the Giant Magellan Telescope at the GMT website. If you are interested in supporting UT’s partnership in the project, please contact development officer Joel Barna by email or by calling 512-471-6335.

Images courtesy of
Carnegie Observatories.
Artwork by Todd Mason.

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