Gemini Observatory

The Gemini Observatory comprises two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, situated in Hawaii and Chile, respectively. These twin telescopes offer extensive coverage of the northern and southern skies and rank among the most advanced optical/infrared telescopes available to astronomers. (See List of largest optical reflecting telescopes).

The observatory is owned and operated by the National Science Foundation (NSF) of the United States, the National Research Council of Canada, CONICYT of Chile, MCTI of Brazil, MCTIP of Argentina, and Korea Astronomy and Space Science Institute (KASI) of Republic of Korea. The NSF is the primary funding contributor, providing about 70% of the required resources. The Association of Universities for Research in Astronomy (AURA) manages the operations and maintenance of the observatory through a cooperative agreement with the NSF, acting as the Executive Agency on behalf of the international partners. NSF's NOIRLab is the US national center for ground-based, nighttime optical astronomy and operates Gemini as one of its programs.

The Gemini telescopes are equipped with modern instruments and excel in optical and near-infrared performance. They utilize adaptive optics technology to counteract atmospheric blurring. Notably, Gemini leads in wide-field adaptive optics assisted infrared imaging and has recently commissioned the Gemini Planet Imager, enabling researchers to directly observe and study exoplanets with extreme faintness compared to their host stars. Gemini supports research across various domains of modern astronomy, including the Solar System, exoplanets, star formation and evolution, galaxy structure and dynamics, supermassive black holes, distant quasars, and the structure of the Universe on large scales.

Previously, Australia and the United Kingdom were also involved in the Gemini Observatory partnership. However, the UK withdrew its funding at the end of 2012. In response, the observatory has significantly reduced operating costs, streamlined operations, and implemented energy-saving measures at both sites. Additionally, both telescopes are now operated remotely from Base Facility Operations centers located in Hilo, Hawaii, and La Serena, Chile. In 2018, KASI has signed an agreement to become a full participant of the Gemini Observatory.

The Gemini Observatory's international Headquarters and Northern Operations Center is located in Hilo, Hawaii at the University of Hawaii at Hilo University Park. The Southern Operations Center is located on the Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile.

Together, the two telescopes cover almost all of the sky except for two areas near the celestial poles: Gemini North cannot point north of declination +89 degrees, and Gemini South cannot point south of declination −89 degrees.

Both Gemini telescopes employ a range of technologies to provide world-leading performance in optical and near-infrared astronomy, including laser guide stars, adaptive optics, multi conjugate adaptive optics, and multi-object spectroscopy. In addition, very high-quality infrared observations are possible due to the advanced protected silver coating applied to each telescope's mirrors, the small secondary mirrors in use (resulting in an f16 focal ratio), and the advanced ventilation systems installed at each site.

It is estimated that the two telescopes cost approximately US$187 million to construct, and a night on each Gemini telescope is worth tens of thousands of U.S. dollars.