More than 300 people traveled thousands of miles to a remote mountaintop in Chile for the dedication of two of the most powerful survey instruments ever built: the Baade and the Clay 6.5-meter reflecting telescopes. Built by the Carnegie Institution for their Las Campanas Observatory, each of the two main mirrors measures over 21 feet in diameter and has a parabolic surface polished to better than one millionth of an inch accuracy.
The Las Campanas Observatory is the southern extension of Carnegie’s historic Mount Wilson Observatory in California, where in 1929 Edwin Hubble discovered that the universe is expanding. Astronomer Walter Baade studied stellar populations in galaxies and, in 1952, startled the world by doubling the scale of the observable universe, and with it, the age derived from the universal expansion.
More recently, in a ground-breaking survey using the Las Campanas 2.5-meter (100-inch) du Pont telescope, Carnegie astronomers discovered that, on scales of about 300 million light years and larger, the distribution of galaxies becomes remarkably uniform in all directions.
With the new telescopes, astronomers hope to understand our origins by studying the chemical history of the first stars in our Galaxy as well as the first galaxies to form near the edge of the observable universe. They will also search for black holes, investigate fiery galaxy collisions, and map the large-scale structure of the universe. An exhaustive search will be made for the wobbles in the orbits of stars surrounded by planets, crucial for estimating the likelihood of life elsewhere in the universe.
The dedication of the telescopes and facility on December 9 will be attended by astronomers and well wishers from many nations, including the President of Chile Ricardo Lagos, and representatives from the Magellan Consortium, which is a scientific collaboration of the Carnegie Institution of Washington, the University of Arizona, Harvard University, the Massachusetts Institute of Technology, and the University of Michigan.
A suite of custom-built instruments, including cameras and spectrographs, will enable observations of great diversity, from local regions of active star formation to cosmologically distant galaxies. Carnegie astronomers designed the telescopes with specific instruments in mind. They designed two of their instruments, named IMACS and MIKE, to enable astronomers to take spectrograms of hundreds of stars or galaxies simultaneously, making the Baade and Clay telescopes among the most efficient in existence.
While IMACS and MIKE will map the growth of existing filamentary structure in galaxies out to more than half the age of the universe (currently thought to be about 14 billion years), some spectacular astronomical events, such as supernovae and gamma-ray bursts, occur suddenly and without notice. One new instrument is a camera aptly named MAGIC that will enable astronomers to image these "targets of opportunity." MAGIC is a cooperative project between the Harvard-Smithsonian Center for Astrophysics and MIT’s Center for Space Research.
The central regions of our Milky Way galaxy are best viewed from the southern hemisphere, as are many of the Milky Way’s most massive star-forming complexes and its neighboring galaxies the Magellanic Clouds, "Las Campanas Observatory ranks among the best sites on earth, and the new telescopes will give U.S. astronomers their main access to the southern hemisphere sky," noted Augustus Oemler, Jr., Director of the Carnegie Observatories.
The five Consortium institutions and their more than 400 astronomers have a long tradition of excellence in cutting-edge research. The new twin telescopes will give the astronomers ample time for innovative and long-term research projects. "The Baade and Clay Telescopes create extraordinary opportunities. These mirrors are our generation’s gift to the future expansion of human horizons," commented Maxine Singer, President of the Carnegie Institution.
Each member of the Magellan Consortium has its own scientific agenda for the two new telescopes, whose large light-collecting mirrors will facilitate observations of distant faint objects. Their uniquely wide fields of view mean that entire clusters of galaxies can be observed simultaneously.
The greatest technical challenge was the fabrication of the 6.5-meter primary mirrors, which represent a radical departure from the conventional solid-glass mirrors used in the past. The new mirrors are honeycombed on the inside, and made out of chunks of borosilicate glass that are melted, molded, and spun into shape in a specially designed rotating oven. These paraboloid mirrors were cast and polished by the University of Arizona Mirror Lab.
As a finale to the ceremony, participants will be able to directly observe a variety of astronomical objects through a special eyepiece and watch as the first of the two 50-foot-high, 150-ton telescopes slews and points with the accuracy of a Swiss watch. These telescopes are so well balanced and nearly frictionless that a gentle sustained push can move all their 150 tons.
IMAGE CAPTION: []    The 50-foot-high 150-ton Baade telescope will be ready for scientific observations in January, 2001.