Ricardo Giovanelli/Cornell University

The summit of Cerro Negro in Chile's Atacama Desert, one possible site for the proposed Caltech-Cornell 25-meter infrared telescope.

Telescope plans for Caltech and Cornell

Caltech and Cornell University have entered the planning phase for a new 25-meter telescope to be built in Chile. The submillimeter telescope will cost an estimated $60 million and will be nearly two times larger in diameter than the largest submillimeter telescope in existence.

The first step of the plan commits the two institutions to a $2 million study, says Jonas Zmuidzinas, a physics professor at Caltech who is leading the Institute’s part of the collaboration. The telescope, to be set high in the Atacama Desert of northern Chile, should be completed in 2012. It will significantly ramp up Caltech’s research in submillimeter astronomy.

Scientists from Cornell, Caltech, and the Jet Propulsion Laboratory will be participating in the telescope study, including Caltech faculty members Andrew Blain, Sunil Golwala, Andrew Lange, Tom Phillips, Anthony Readhead, Anneila Sargent, and others.

“We are very much looking forward to working with our Cornell colleagues on this project,” Zmuidzinas says. At Cornell, the participants will include professors Riccardo Giovanelli, Terry Herter, Gordon Stacey, and Bob Brown.

Submillimeter-wavelength astronomy allows the study of a number of astrophysical phenomena that do not emit much visible or infrared light. The new telescope will observe stars and planets forming from swirling disks of gas and dust, will make measurements to determine the composition of the molecular clouds from which the stars are born, and might even discover galaxies undergoing huge bursts of star formation in the very distant universe. The telescope could also be used to study the origin of large-scale structures in the universe.

“So far, we have gotten just a small taste of what there is to learn at submillimeter wavelengths,” says Zmuidzinas. “This telescope will be a huge step forward for the field.”

The new telescope would be poised to take advantage of the rapid development of sensitive superconducting detectors, an area in which Zmuidzinas and his Caltech/JPL colleagues have been making important contributions. The superconducting detectors enable large and very sensitive submillimeter cameras to be built, which produce panoramic images of the submillimeter sky.

The 25-meter telescope is a natural progression in Caltech and JPL’s longstanding interest in submillimeter astronomy. Caltech already operates the Caltech Submillimeter Observatory (CSO), a 10.4-meter telescope constructed and operated with funding from the National Science Foundation, with Tom Phillips serving as director.

The telescope is fitted with sensitive submillimeter detectors and cameras, many of which were developed in collaboration with JPL, making it ideal for seeking out and observing the diffuse gases and their constituent molecules.

The advantages of the new telescope will be fourfold. First, due to the larger size of its mirror and its more accurate surface, the 25-meter telescope should provide six to 12 times the light-gathering ability of the CSO, depending on the exact wavelength. Second, the larger diameter and better surface will result in much sharper images of the sky. Third, the large new cameras will provide advantages over those now available.

Finally, the 16,500-foot elevation of the Atacama Desert will provide an especially dry sky for maximum effectiveness. Submillimeter wavelengths (as short as two-tenths of a millimeter) are absorbed by the water vapor in the atmosphere. For maximum effectiveness, a submillimeter telescope must be located at a very high and dry altitude or in space.
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