The northern Gemini telescope being built in Hawaii is an example of international cost-sharing of a facility on U.S. soil. Cerro Tololo Interamerican Observatory is a complex of astronomical telescopes and instruments located approximately 80 km to the East of La Serena, Chile at an altitude of 2200 Meters. CTIO's facilities are available for use for approved projects by all qualified astronomers in the western hemisphere. Eighty per cent of the staff are Chilean nationals. The facilities are used by about 200 visiting scientists each year.
Chile is allocated ten per cent of the observing time.
The telescopes and auxiliary instrumentation will be international facilities open to the scientific communities of the member countries. Siting the telescopes in Hawaii and in central Chile will provide complete sky coverage, making key astronomical objects accessible regardless of location on the celestial sphere. Both sites offer high percentages of clear weather and excellent atmospheric stability. An MMA site is being considered at Llano de Chajnantor, Chile. MPS is actively seeking international partners for MMA, as they have successfully done for GONG, and the Gemini Telescopes.