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About Caltech Astronomy

Astronomer Royal of the United Kingdom, Martin Rees, summed up Caltech's legacy in astronomy when he said, "The universe of astronomy has no center, but the universe of astronomers does. For years that center has been in Pasadena, California."

As part of Caltech's Division of Physics, Mathematics and Astronomy, the astronomy department's primary mission is to perform cutting-edge research in astronomy and astrophysics while educating undergraduate and graduate students to become the scientific leaders of tomorrow.

Astronomy has been a major component of Caltech's scientific identity since the early days of the Institute. George Ellery Hale, the first director of the Mount Wilson Observatory, was elected to the board of trustees of Throop Polytechnic Institute (later to be renamed the California Institute of Technology) in 1907. Hale is largely responsible for shifting the institution's focus to engineering and science, fields in which Caltech would quickly become a world leader.

Among Caltech's major contributions to the field of astronomy is the first survey of the entire sky visible from the Northern Hemisphere, the Palomar Observatory Sky Survey. Conducted in l948, it revealed thousands of new stars, galaxies, and comets. This provided astronomers the world over with an atlas of the heavens to be used for the next three decades. Today, Palomar Mountain in San Diego County is home to the 200-inch Hale Telescope, which was for four decades the largest and most powerful optical telescope in the Western Hemisphere.

In 1964, Caltech astronomer Maarten Schmidt determined that quasars--a puzzling class of cosmic objects--were the most powerful and distant objects in the universe. Since quasar light travels for billions of years to reach Earth, Schmidt's discovery gave astronomers unprecedented insight into how the universe looked billions of years before the birth of the sun and its planets.

Today, the Caltech astronomy department--led by more than 30 faculty--continues to engage in a wide variety of astronomical research projects, with topics ranging from nearby stars to the most distant galaxies in the universe. To help maintain these research efforts, the department supports an interest in worldwide astronomical observatories at locations ranging from San Diego County to Hawaii to the Chilean Andes, including

The Palomar Observatory, located in San Diego County, was dedicated in 1948 and is home to the 200-inch Hale Telescope, as well as a 60-inch instrument, the 48-inch Samuel Oschin Telescope, and an 18-inch Schmidt Telescope.

The Laser Interferometer Gravitational-Wave Observatory, or LIGO, is dedicated to the detection of cosmic gravitational waves and the harnessing of these waves for scientific research. Albert Einstein predicted the existence of these waves in 1916, and LIGO--which was designed by Caltech and MIT physicists--began its search in 2001. LIGO consists of two widely separated installations within the United States--one in Hanford, Washington, and the other in Livingston, Louisiana--which are operated in unison as a single observatory.

The Keck Observatory is perched atop the dormant volcano Mauna Kea on the island of Hawaii. Keck is a joint effort of Caltech and the University of California, and consists of twin 10-meter telescopes, Keck I and Keck II. Recently, the two telescopes have been used in combination as the Keck Interferometer, with sufficient power and resolution to detect planetary systems around nearby stars.

The Caltech Submillimeter Observatory is a 10-meter dish atop Mauna Kea in Hawaii.

The Owens Valley Radio Observatory is located some five hours north of Pasadena, near the Sierra Nevada range. The observatory is home to a variety of dishes and interferometers, and is the operations base for the CARMA millimeter-wave interferometer (see below).

The Combined Array for Research in Millimeter-wave Astronomy, or CARMA, is the merger of two university-based millimeter arrays--the Owens Valley Radio Observatory (OVRO) millimeter array and the Berkeley-Illinois-Maryland Association (BIMA) millimeter array--which together form a powerful astronomical tool for the new millennium.

The Chajnantor Observatory is located at an altitude of over 16,000 feet in the Chilean Andes. It is the site of the Cosmic Background Imager (CBI) and will be the site of the Q/U Imaging Experiment (QUIET) project. The site is accessible year-round and provides superb conditions for cosmic microwave background observations.

The Thirty Meter Telescope is a collaboration between Caltech, the University of California, and the Association of Canadian Universities for Research in Astronomy (ACURA) to build a 30-meter-diameter telescope for astronomy at visible and infrared wavelengths.

The Big Bear Solar Observatory is a world center for observations of the sun. The facility is managed by the New Jersey Institute of Technology for a university consortium that includes Caltech.

Visit to learn more about Caltech Astronomy.

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Written by Lori Oliwenstein

Caltech Media Relations