Mauna Kea is by far the largest astronomical observatory, located in Hawaii and named after the extinct volcano on which it is built. The observatory is 4200 meters above sea level, which makes it ideal for infrared astronomy: dry air, high above clouds and artificial lighting. The first telescope was set up in 1970.

The scene is in hands of the University of Hawaii's Institute for Astronomy, but many countries have installed telescopes here. The University itself has the oldest telescope here, which dates back as far as the birth of the observatory (1970). The world's largest optical telescopes are the W.M. Keck I and II, each with a mirror of 10 meters across and an array of 36 2-meter hexagonal segments joined together in a giant mosaic. Each segment is controlled and adjusted by computer to generate single images of the objects observed. Other large telescopes are those of Chile (Gemini), Japan (Subaru), United Kingdom / The Netherlands (James Clerk Maxwell, the world's largest submillimeter telescope) and Canada / France / Hawaii (CFHT).

Mauna Kea is Hawaiian for white mountain and situated on the large Hawaii island, located about 300 kilometres from capital Honolulu. A visitor information station at Mauna Kea is open to the public.

Mauna Kea's most informative website is at