The 8-meter Frederick C. Gillett Gemini North telescope is located near the summit of Hawai‘i’s Maunakea — a long dormant volcano rising 4,214 meters into the dry, stable air of the North Pacific. Gemini North was designed and built, in part, to provide the best image quality possible from the ground for telescopes of its size.
Four significant features help the telescope achieve this goal: (1) An ~20-centimeter-thin primary mirror on a bed of 120 hydraulic actuators; (2) a 1-meter-diameter secondary mirror capable of rapid tip-tilt corrective motions; (3) vents on the cylindrical walls to provide a smooth flow of air above the primary mirror, and to regulate the temperature of the air above the mirror to match the outside temperature; and (4) an adaptive optics system which can correct for image blurring caused by atmospheric turbulence.
Gemini North and its twin telescope in Chile are the only large telescopes in the world with silver-coated primary mirrors. These special coatings make the telescopes excel in a wide variety of optical and infrared capabilities, allowing astronomers in the Gemini Partnership to explore the Universe in unprecedented depth and detail.