The Gemini Project is an international partnership to construct and operate two 8-meter optical-infrared telescopes, one on Mauna Kea, Hawaii and the other on Cerro Pachón, Chile. The sites were chosen to provide good access to both hemispheres, in optimal conditions for optical and infrared observations, where an astronomical infrastructure already exists. Although the telescopes will be identical, their initial instrumentation will differ because of both scientific and financial considerations.

As this is the first annual report of the Gemini Project, a full description of the Project and a summary of the scientific investigations to be undertaken with the Gemini telescopes is of interest. An illustrated brochure entitled The International Gemini Telescopes, containing such a description, has been prepared for distribution to the public.

The International Partnership

The six international partners in the Gemini Project, the agencies that represent them, and their proportional financial shares in Gemini are listed in the following table:

United StatesNational Science Foundation (NSF)50%
United KingdomParticle Physics and Astronomy Research Council (PPARC)25%
CanadaNational Research Council (NRC)15%
ChileComisión Nacional de Investigación Científica y Tecnológica (CONICYT)5%
BrazilMinistry of Science and Technology (MST)2.5%
ArgentinaSecretaría de Ciencia y Tecnologia (SECYT) & Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)2.5%

Each partner contributes the indicated share of the capital construction cost, and receives in return a proportionate share of observing time on both telescopes. Since the northern site is provided by the University of Hawaii, a share of the observing time at that site will go to the University of Hawaii. Similarly, since Chile has supplied the southern site, an additional share of the observing time at the southern telescope will go to Chilean astronomers.

In addition to observing time, the intellectual value involved in designing and constructing the telescopes is also shared among the member nations.

Science specifications

The 8-meter primary mirrors are an f/1.8 thin meniscus design. The highest scientific priority has been given to obtaining outstanding image quality, particularly in the infrared. With wavefront-tilt correction and adaptive optics, the Gemini telescopes will deliver image quality better than 0.1 arcsec over a 1 arcmin field at the near-IR wavelength of 2.2µm. Adaptive optics capabilities will extend this near-diffraction- limited angular resolution to shorter wavelengths. Either silver or aluminum coatings will be available, to achieve high performance over a broad wavelength range. An optimized IR configuration will provide extremely low emissivity, with a goal of 2% for the Gemini North telescope.

All first-generation instruments will be located at the f/16 Cassegrain focal platform. The planned baseline instrumentation is:

Mauna KeaCerro Pachón
Optical Acquisition CameraOptical Acquisition Camera
Multi-Object Spectrograph (UK/Canada)Multi-Object Spectrograph (UK/Canada)
1-5µm Imager (U. of Hawaii)High Resolution Optical Spectrograph (UK)
1-5µm Spectrograph (US NOAO)Shared Instrumentation with CTIO
8-30µm Imager (US) (May be shared between Gemini North and South)
CFHT Fiber Feed

International Work Packages

Since the partnership aspect of the Gemini Project involves sharing of intellectual value as well as of costs, each partner is contributing to the telescope or instrumentation design. The US is designing and building the near-IR Imager and Spectrograph, the IR arrays, and the controllers; the UK is designing the telescope system controls, including acquisition and guiding, and building much of them, as well as the High Resolution Optical Spectrograph; Canada is designing the adaptive optics; the UK and Canada are providing the Multi-Object Spectrographs; and Chile is participating in the CCD development program with the US.


The schedule for the Gemini Project is shown in Table 1.

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