An Introduction

The Gemini Project is an international partnership to build two 8-meter telescopes, one on Mauna Kea, Hawaii, and one on Cerro Pachon, Chile. The telescopes and auxiliary instrumentation will be international facilities open to the scientific communities of the member countries.

Siting the telescopes on Mauna Kea (elevation 13,882 ft/4253 m) in Hawaii and Cerro Pachon (elevation 8895 ft/2737 m) near Cerro Tololo in central Chile will provide complete sky coverage, making key astronomical objects (e.g. Magellanic Clouds, M31, M32, and M33) accessible regardless of location on the celestial sphere. Both sites offer high percentages of clear weather and excellent atmospheric stability.

The Gemini telescopes are designed to exploit the best image quality allowed by the Earth's atmosphere at these sites. Images approaching 0.1 arcsec in size will be achieved near 2.2µm, with near diffraction limited imaging at longer wavelengths. Optical images of <0.3 arcsec, well suited to correction via adaptive optics, will be achieved.

Gemini IR performance, especially on Mauna Kea, will be further enhanced by minimizing the telescope contributions to the thermal IR backgrounds. The combination of large aperture, excellent imaging, and low IR background give the Gemini Telescopes an order of magnitude sensitivity increase over existing 4-meter class telescopes for many applications.

Initial instruments will provide a basic set of capabilities for IR and optical imaging and spectroscopy. Instruments will be constructed as work packages to be managed by the national project offices in the partner countries.

Ruth A. Kneale / / April 13, 1999