Lots of scope

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A 25-metre, far-infrared telescope will be located in the Chilean desert to probe the outer reaches of the solar system.

The University of Colorado at Boulder has signed an initial partnership agreement to participate in the design and construction of a 25-metre, far-infrared telescope that will be located in the Chilean desert to probe the distant galaxies, stellar nurseries and outer reaches of the solar system.

CU-Boulder and the United Kingdom Astronomy Technology Centre, based at the Royal Observatory in Edinburgh, Scotland, will collaborate with the two major partners, Cornell University and the California Institute of Technology, on the $100 million project, slated for completion in 2013.

The telescope will be built in the Atacama Desert in Chile at an altitude of about 18,000 feet and will be the largest, most precise and highest astronomical facility of its kind in the world, said Associate Professor Jason Glenn of the astrophysical and planetary sciences department who is spearheading the CU-Boulder portion of the project.

The Cornell Caltech Atacama Telescope, or CCAT, will gather radiation from sub-millimetre wavelengths, which are longer than visible and infrared light but shorter than radio waves, said Glenn. 'This facility will enable us to study the earliest stages of star and galaxy formation, as well as the initial conditions of the solar systems like our own,' he said.

The project partners are raising the estimated $100 million needed for the construction of the telescope through private donations, about half of which already has been committed by major partners. Fundraising by CU-Boulder, which has just begun, will require roughly $5 million in capital toward the cost of the facility, Glenn said.

Technology for the telescope's instruments already is being developed at CU-Boulder. Glenn's lab at the Center for Astrophysics and Space Astronomy has received a $1.1 million grant from the National Science Foundation to build a camera using an array of 600 superconducting detectors, each of which will be able to measure four colours simultaneously. The NSF grant is being matched by a grant to Cal Tech from the Gordon and Betty Moore Foundation in San Francisco.

CU-Boulder will collaborate with scientists and engineers at the National Institute of Standards and Technology -- which has one of the premier sub-millimetre detector research groups in the world -- on instrument development, he said.

Since sub-millimetre waves are absorbed by water vapour in Earth's atmosphere and are difficult to detect from the ground, the research team chose the Atacama Desert - one of the highest, driest places on Earth - for the telescope. Blocked from coastal moisture by the Andes, parts of the Atacama Desert have been reported to be rainless for decades at a stretch. The region is considered the premier locale in the world for sub-millimetre astronomy, Glenn said.

'This telescope will be up to 30 times more sensitive than existing sub-millimetre telescopes, allowing us to look back in time to when galaxies first appeared,' he said.

Due to the particular spectral "signature" of galaxies in the sub-millimetre range, those forming just a billion or so years after the big Bang will appear to be as bright as less distant galaxies, allowing astronomers to probe their earliest formation in the universe, Glenn said.

CCAT is being designed to work in concert with the proposed Atacama Large Millimeter Array, or ALMA, also in Chile, he said. ALMA consists of a set of mobile radio antennas similar to the Very Large Array in New Mexico that can be reconfigured to target distant astronomical galaxies and stars in sub-millimetre wavelengths. Once CCAT locates particularly compelling astronomical targets, ALMA will be used to "zoom in" for further, more refined observations, he said.

The new telescope will be a workhorse instrument for astronomers for decades because about half of the light emanating from distant stars and galaxies reaches Earth at far-infrared and sub-millimetre wavelengths. Newly forming stars and solar systems are surrounded by gas and dust, which block the escape of visible light but which radiate at these wavelengths.