[ASA] News from GMTO
john.obyrne at sydney.edu.au
Fri Jun 7 10:34:52 AEST 2013
Moving a Mountain to See the Stars
The Giant Magellan Telescope will have to function as an extremely precise instrument in order to counter the earth's rotation in 23-hours, 56 minutes and 4.1 seconds. The GMT structure will be anchored firmly to its mountaintop bedrock base to avoid the smallest vibrations. If not firmly anchored, vibrations would make their way up through the steel structure to the mirrors as the 1,100-ton telescope rotates and pivots, shaking the telescope and causing stars' images to blur.
Months of meticulously planned blasting in 2012 have removed over 90,000 cubic meters of extremely hard bedrock--about the weight of the Empire State Building--from the 8,500-foot peak high in the Atacama Desert. In addition, a geotechnical survey was carried out 200 feet below grade. This is equivalent to getting a "CAT scan" of the mountain peak. The survey and other seismic tests will inform the design and specifications of the foundation and enclosure. The results of the survey and seismic tests are being studied carefully to determine how much concrete and steel will be needed for the foundation of the telescope. GMT engineers now feel confident that their machine will "see" the stars with unprecedented stability and clarity from the Cerro Las Campanas mountain peak.
GMT Enclosure Passes Critical Test
At over 200 feet tall--the height of a 20-story building--the GMT Enclosure will accommodate one of the largest ground-based telescopes ever built. Its shutters must protect sensitive optics and instruments from winds that can reach 120 mph on a high mountain peak, while delivering high-resolution images from the universe. Is the enclosure design the right approach to meeting science and operational needs and goals? Can it be built with current engineering technology or will new technology need to be developed? Can the enclosure be built within budget parameters?
On January 18th, the GMTO Enclosure and Facilities Group successfully answered all of these questions and many others by passing its Preliminary Design Review (PDR). Now the group moves on to the Construction Document phase, followed by Final Design, and then actual construction.
Lead Mechanical/Structural Engineer Arash Farahani described why the Enclosure team was so elated at the news, "Other groups will need the Enclosure and Facilities to be on site before they can start work; the project completion date would have been affected if the Enclosure design was delayed."
During science operations, the Enclosure must allow the telescope to operate to its maximum capability, while providing ultimate protection from the sometimes-harsh environment at the summit of Las Campanas peak. The GMTO team found sophisticated solutions to these challenges.
Welcome Bret Schaefer - GMT C.F.O.
He began as a history major at the University of Chicago,and eventually managed international operations financing for one of Silicon Valley's most successful start-ups. Today, he is overseeing the financial dynamics of building the biggest telescope on Earth. Meet Bret Schaefer - GMT's new Chief Financial Officer.
What makes Bret an asset to GMT? "I guess one way to think about it is that I bring Fortune 100-level financial and investor relations expertise. What you learn in the start-up world is that you have to have a small team that is very effective and versatile--but also is capable of engaging with the experts that you need in order to deliver the project."
Bret spent nearly 20 years at Sun Microsystems and later helped several non-profit organizations establish long-term financial planning to sustain and grow their operations. Now Bret looks forward to growing with GMT. "You don't see opportunities with projects that have this kind of impact very often."
GMT's "Workhorse" Instrument Will See Early Universe
A marvel of engineering and about the weight of a large pickup truck, one of the instruments being designed for early use on the GMT will be located underneath the Giant Magellan Telescope's central mirror. Each night, it will gather and dissect very faint infrared light to help solve the mysteries of how galaxies and black holes form and grow over billions of years. Known as "GMTIFS"-- The GMT Integral Field Spectrograph--it will be one of the key Adaptive Optics (AO) instruments used by the observatory. GMT recently held a workshop on March 12th and 13th in Pasadena to discuss the current design of the sophisticated instrument and collect valuable input from the international astronomy community as a key step toward finalizing the instrument's design. Below is a brief video of the meeting:
GMTIFS Science Meeting, Pasadena, CA - March 12, 2013
The Australian National University, a GMT partner, is designing the instrument. GMTIFS will operate in two ways, using only natural guide stars as reference, or using the six artificial guide star constellation provided by powerful lasers launched from within the telescope enclosure. These laser beams illuminate sodium atoms in the mesosphere - some 90 kilometers above the Earth's surface and create "artificial stars" - reference points for the GMT AO system.
Copyright © 2013, GMTO Corporation. All Rights Reserved.
This email was sent to john.obyrne at sydney.edu.au by info at gmto.org |
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