Gemini North Telescope at sunset

The Gemini Observatory consists of twin 8.1-meter diameter optical/infrared telescopes located on two superb observing sites. From their locations on mountains in Hawai’i and Chile, the Gemini telescopes can collectively access the entire sky.

The Gemini South telescope is located at about 2,750 meters (8,900 feet) elevation on Cerro Pachón, a mountain in the Chilean Andes. Cerro Pachón shares resources with the adjacent SOAR telescope and the nearby telescopes of the Cerro Tololo Inter-American Observatory. The Frederick C. Gillett Gemini North telescope is located at an elevation of about 4,200 meters (13,800 feet) on Hawaii’s summit of Mauna Kea, and is part of an international community of observatories located on this dry, stable site. Both of the Gemini telescopes feature primary mirrors with protected silver coatings, one of several optimizations leading to their enhanced performance in the infrared. Several thermal control systems contribute to the telescopes’ excellent delivered image quality.

Gemini was built and is operated by a partnership of 7 countries including the United States, United Kingdom, Canada, Chile, Australia, Brazil and Argentina. The U.S. partner share is ~50% of each telescope. The NOAO System Science Center, located in Tucson, AZ, manages the U.S. share in Gemini. The Gemini Observatory’s international headquarters is located in Hilo, Hawai’i.

Gemini observations may be taken in queue mode, where Gemini staff observe programs in priority order according to their scientific rank and the availability of their desired observing conditions, or in classical mode, where visiting observers take their own data on regularly scheduled nights. The Gemini telescopes have been integrated with modern networking technologies to allow remote operations from control rooms at the base facilities in Hilo and La Serena Chile.

Gemini Observatory
Northern Operations Center
670 N. A’ohoku Place
Hilo, Hawaii, 96720, USA
Phone: (808) 974-2500
Fax: (808) 974-2589

Gemini Observatory
Southern Operations Center
c/o AURA, Casilla 603
La Serena, Chile
Phone: 56-51-205-600
Fax: 56-51-205-650

Last updated or reviewed February 23, 2011.