TABLE 3.3 Existing and Approved Large Ground-Based Optical and Infrared Telescopes

Project

Commencement of Operations

Partners Involved

Percent U.S.

Aperturesa

Gemini

 

United States, United Kingdom,

 

 

Northern

1999

Canada, Chile, Australia,

52

2 × 8 m

Southern

2001

Argentina, Brazil

42

 

Gran Telescopio Canarias

2003

Spain

0

1 × 10.4 m

HET

1998

United States,b Germany

90

1 × 9.2 m

Keck

1993, 1996

United Statesb

100

2 × 10 m

LBT

2002

United States,b Italy, Germany

50

2 × 8.4 m

Magellan

2000, 2002

United States,b Chile

90

2 × 6.5 m

MMT

1999

United Statesb

100

1 × 6.5 m

SALT

2002

South Africa, United States,b Poland, New Zealand, Germany, United Kingdom

20+

1 × 10 m

Subaru

1999

Japan

0

1 × 8 m

VLT

1999+

Europe

0

4 × 8 m

aNotation: 2 × 8 m denotes two telescopes with 8-m-diameter apertures.

bU.S. private or university telescopes.

SOURCE: Includes data from NRC (2000), Table 5.13.

advantage of the effort to cool the instrument, but NGST would also gain its greatest advantage over any ground-based telescope at the longer infrared wavelengths (see Figure 3.3).

Considerable progress has been made in developing the challenging technology required by NGST, including sensitive detectors, lightweight deployable primary mirrors, and control and image analysis systems. To enable NGST to reach its full potential, the committee recommends technology development to increase telemetry rates in spacecraft communication and for cryocoolers that enable detectors to operate at wavelengths longer than 5 µm.

GSMT complements NGST, both in technical capabilities and in its ability to probe distant galaxies and nearby star-forming regions. GSMT is a 30-m-class, ground-based, filled-aperture, segmented-mirror, optical and infrared telescope that will operate in the atmospheric windows over the wavelength range from 0.3 to 25 µm. Adaptive optics will give it diffraction-limited performance down to wavelengths as short as 1 µm. GSMT will complement NGST much as the Keck telescope has comple-



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