Ceremonies in 1994 October in both the northern and southern hemispheres will herald construction of the $176 million, 8.1-meter Gemini twin telescopes. Ground-breaking will take place October 6 for the northern telescope on Mauna Kea, Hawaii, followed by an October 22 inauguration for construction of the southern telescope in Cerro Pachon, Chile.
The light-gathering power of the huge mirrors, coupled with the superb imaging-ability of the optical systems, will render these new generation telescopes ten times more sensitive than existing 4-meter telescopes. Astronomers will use the Gemini telescopes' power to study some great astronomical questions, such as the origin of planets, stars, the solar system, chemical elements, quasars, active galactic nucleii, and galaxies. Gemini will also be used to explore the frontiers of cosmology.
The international Gemini partnership consists of the United States, the United Kingdom, Canada, Chile, Argentina, and Brazil. The U.S. National Science Foundation administers the project for the partnership and provides half the support. The project is managed by the Association of Universities for Research in Astronomy under cooperative agreement with NSF.
Together, the two telescopes will provide coverage of the entire sky, in both visible and infrared wavelengths. Building two telescopes from a common design will also save considerably on engineering and fabrication costs. Infrared images from the northern site, in particular, should be comparable to or better than optical images from the Hubble Space Telescope.
The Gemini twins will occupy astronomically superb sites. Mauna Kea is viewed as the best all-around observing site in the Northern Hemisphere. At 4200 meters, it towers above much of the atmospheric water vapor that hampers most observations from Earth into space. Ground-breaking on Mauna Kea will begin with a traditional blessing by a Hawaiian religious leader. In Chile, Cerro Pachon, 2700 meters high, sits within the dry mountains of the Atacama desert and offers an atmosphere for astronomical observation as good as any site in the Southern Hemisphere.
Gemini will be particularly suited for investigating the origins of stars and galaxies. The dust shrouds of young stars can best be parted at infrared wavelengths, revealing the stars at the earliest epochs of their formation. The telescopes will also enable probes of how the farthest known galaxies were formed and evolved.
Corning Glass of New York is producing primary mirrors for both telescopes. Each mirror consists of 42 hexagonal blocks of untra-low-expansion glass, fused into one large, thin disk. The disks will be shipped by boat for polishing at REOSC Optique in France. Canada's Coast Steel Fabrication, Ltd. will build the telescope enclosure. National astronomy laboratories and universities from the partner countries are designing and building Gemini's scientific instruments.
"First light", or inaugural observations, are expected in Hawaii in 1998, with full operation in 2000. The Chilean telescope will see first light in the year 2000, with full operation two years hence.