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About Gemini

The NOAO Gemini Science Center (NGSC) at NOAO is the gateway for the U.S. astronomical community to the international Gemini Observatory Project. The Gemini project is a multi-national collaboration to provide twin 8 meter astronomical telescopes utilizing new technology to produce some of the sharpest views of the universe ever. One telescope is located on Hawai'i's Mauna Kea (Gemini North) and the other on Cerro Pachón in central Chile (Gemini South). Together they will provide complete unobstructed coverage of both the northern and southern skies. Astronomers will use Gemini to probe the cosmos, from planets circling other stars, to the heart of our own galaxy, to the formation of the first galaxies in the universe.

The Gemini telescopes are the largest, most advanced optical/ infrared telescopes available to astronomers in the U.S.A. regardless of institutional affiliation. The Gemini Observatory provides the astronomical communities in each partner country with state-of-the-art astronomical facilities that will allocate observing time in proportion to each country's contribution. U.S. astronomers receive 42% of the observing time on Gemini. In addition to financial support, each country contributes scientific and technical resources. Significant support of the construction, operation, and instruments has been provided by the U.S. National Science Foundation (NSF) as well as several U.S. universities, private industry, and NOAO.

Gemini Project Status
The Gemini North Telescope on Mauna Kea is nearing completion, and science observations began during the summer, 2000, with two visiting instruments, an adaptive optics imager on loan from the University of Hawai'i and a 10-20 micron imager/spectrometer from the University of Florida. The first facility instrument, a Near-Infrared Imager (NIRI) built at the University of Hawai'i, is being commissioned at Gemini North, and a second facility instrument, an optical spectrograph, is expected soon.

The Gemini South Telescope has seen first light at its site on Cerro Pachon in northern Chile. Science observations are expected to begin mid-year in 2001.

Infrared Radiation
Some especially intriguing areas of our universe are those hidden from view, at visible wavelengths, by clouds of gas and dust. Such areas include those where stars and planets form as well as cores of galaxies where black holes might reside. The infrared part of the electromagnetic spectrum encompasses the wavelengths just beyond and longer than visible wavelengths. These longer wavelengths penetrate the clouds of gas and dust so one can see details otherwise hidden from view. Gemini's ability will take us to the core of our own and other galaxies to provide new insights into the violent events that dwell in these areas.

Active Optics
Gemini's huge mirrors will collect more of the often sparse light from space thus improving our window to the universe. With its new technology, Gemini should lead the way for a new generation of large telescopes. In the past, large mirrors were limited by the fact that they had to be excessively thick in order to keep their shape. Active optics enable Gemini's 8.1 meter primary mirror to be relatively thin while maintaining its precise shape. Mounted behind the mirror are 120 "actuators" that constantly nudge the mirror back into perfect form. These adjustments are typically only about 1/1,000 the thickness of a human hair and are enough to keep starlight precisely focused so astronomers can study the universe.

Adaptive Optics
Turbulence in our atmosphere distorts light, causing stars to twinkle. Large telescopes magnify the distortion so that, untreated, a point of starlight looks more like a blurry blob. "Wind shake" and thermal effects add to the problem. On Gemini a relatively new technology called Adaptive Optics (AO) will be used to straighten the light out again. The AO system takes a sample of light, determines how the atmosphere bent it, and makes very small adjustments to a deformable mirror which counteracts the distortions caused by the atmosphere. The secondary mirror at the top of the telescope also can be adjusted up to a hundred times per second to help compensate.

AO systems work best with longer wavelengths so Gemini's infrared observations will yield the most dramatic results. Gemini should produce the sharpest images yet of the infrared sky and dramatically improve many other types of observations as well.

Remote Access
Telescope commands and astronomical data are transmitted electronically between the northern and southern telescopes and their control centers in Hilo, Hawaii and La Serena, Chile. Such remote operations allow scientists and engineers to conduct their precision work in the more hospitable environment at sea-level.

State-of-the-Art Instrumentation
The partners are developing a suite of instruments to complement these high-tech telescopes. With superb optical and infrared capabilities, we will probe areas of our universe with more clarity than ever before. Ultra-sensitive detectors and the latest optical and computer technology will make these two of the best equipped telescopes on our planet.

U.S. Work Packages for Gemini
Many of the work packages for the construction of the Gemini Observatory were carried out in the U.S.

NSF Support of Gemini
Financial support for U.S. participation in the Gemini project was provided by the National Science Foundation.

NOAO is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under cooperative agreement with the National Science Foundation. The NGSC represents U.S. scientific, technical, and instrumentation interests in the international community of the Gemini project. The NGSC is a division of the National Optical Astronomy Observatories (NOAO).

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