News Release

Giant, priceless telescope mirror treks from Tucson to Chile via L.A.

Peer-Reviewed Publication

Carnegie Institution for Science

On November 8, 1999, an enormous, fragile, multimillion-dollar telescope mirror embarked on a 3 1/2-week journey from the world-renowned Steward Observatory Mirror Lab at the University of Arizona to the Carnegie Institution of Washington's Las Campanas Observatory in the Chilean Andes. The 21.3 foot-wide (6.5 meters) mirror weighing 9.5 tons is cocooned in a 14.5-ton protective box. The three-lane-wide-load traveled on I-10 with a police escort from Tucson, Arizona to the California border. The convoy proceeded to the Port of Los Angeles, where it arrived at 3:00 a.m., November 9. The mirror and accompanying equipment will be loaded midday November 12 onto a Columbus Line ship at the Port of Los Angeles for a 16- day voyage to the small historic port of Coquimbo, Chile. Once there, another huge truck will take it through the town's narrow and winding streets to the Pan American Highway. It will be escorted again on the last leg of its journey high into the Andes to Las Campanas. (Broadcast- quality video of the journey, from Arizona, across the Arizona/California border, to the Port of Los Angeles, is available from Karen Gross at the Carnegie Observatories, 626-304-0227.)

The mirror is the first of two 6.5-meter mirrors to be installed as part of the Magellan Twin Telescope project at the Las Campanas Observatory. Matt Johns of the Observatories of the Carnegie Institution of Washington is project manager, while Stephen Shectman, also with Carnegie, is the project scientist. The site, 2,200 meters above sea level in the Sierra del Condor, and 40 kilometers from the coast, is in the southern part of Chile's Atacama Desert, the driest on Earth. It is unsurpassed for astronomical observations because of its dry and stable atmosphere, and the absence of light and dust pollution. The southern hemisphere location also offers a view of skies not available in the north, and a chance to study features such as the center of our Milky Way and our closest galactic neighbors, the Large and Small Magellanic Clouds.

Planning for the Magellan project began at Carnegie in 1986. The telescopes have a unique optical design, which will permit them to simultaneously observe large areas of the sky. The combination of telescope size and wide-angle coverage will give them a power unsurpassed by any other telescopes currently being built. These telescopes will provide over half the total observing capability available to U.S. astronomers in the southern hemisphere. Astronomers from Carnegie and its partners, Harvard University, the Massachusetts Institute of Technology, and the Universities of Arizona and Michigan, will use them for studies of the structure and history of the Milky Way, the formation of stars and planets, and the structure and evolution of the universe.

It takes a long time to make a telescope mirror; each step is painstakingly precise. The state-of- the art honeycomb design for Magellan is a product of Roger Angel's Steward Observatory Mirror Lab at the University of Arizona. Months were spent fabricating the mirror mold: some 1,000 hexagonal ceramic cores had to be installed individually. Then, more than eleven tons of glass, in eight-pound chunks, were inspected and placed on the mold's surface. In February 1994, the material was cooked in a rotating heating unit to create the parabolic shape integral to the unique design. The mirror blank for Magellan I had to cool slowly; and it could not even be inspected until late that April. Since then, the primary mirror has been delicately lifted from the turntable, slowly washed, ground, polished, coated, and tested. Each stage has been meticulously monitored, and as a result, the Magellan I mirror is perhaps the best large telescope mirror ever produced. By May of 2000, Magellan I will start collecting light, and in October of 2002 its twin, Magellan II, will be ready for work.

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The Carnegie Institution of Washington ( http://www.ciw.edu ), a private, nonprofit organization, engages in basic research and advanced education in biology, astronomy, and the earth sciences. There are five research departments in the U.S.: Terrestrial Magnetism, Plant Biology, Observatories, Embryology, and Geophysical Laboratory.

Astronomers at the Observatories, established in 1904 and headquartered in Pasadena, California, conduct programs of research on many topics. Among these include the structure and dimensions of the universe and the physical nature, chemical composition, and evolution of celestial objects. The department also has an observational facility and staff in Las Campanas, Chile. It is here, high in the Andes, that Carnegie astronomers make most of their observations. Las Campanas is the site of Carnegie's 2.5-meter du Pont Telescope and the 1-meter Swope Telescope. Soon these telescopes will be joined by the two from the Magellan project.


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