A New Eye on the Sky

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In an office in the UW's new astronomy building, a graduate student sits before a computer screen and types a command. The signal rushes over the Internet to a remote location in southwest New Mexico. There, in the rarefied air high atop a 9,200-ft peak, the huge observatory doors rumble open, as Apache Point's fully remote-controlled, ground-based telescope trains its eye on the night's celestial subject.

Until the advent of the Apache Point Telescope, that scenario was an unlikely one. Astronomers usually had to venture to remote corners of the globe in order to access the world's best telescopes. Now, the mountain can come to the astronomer.

Owned and operated by the UW jointly with five partner universities, the Apache Point Telescope has a revolutionary design that makes it lighter and more inexpensive than was previously possible. And the ability to use the telescope remotely by computer makes it more efficient, flexible, and accessible than other large telescopes.

The new mirror technology was developed in the early 1980s by University of Arizona astronomy Roger Angel. By building a mirror as a sheet of glass on top of a glass honeycomb structure, Angel could make mirrors that were lighter, cheaper, and simpler than ever before. And because Angel's mirrors could adjust more rapidly to changes in air temperature after sunset, they reduced distortion in astronomical images.

Angel and UW astronomer Bruce Margon teamed up in the early 1980s to promote construction of the Apache Point Telescope, made possible in part by a grant from the National Science Foundation. Dedicated in the spring of 1994, the telescope is owned and operated by six universities that constitute part of the Astrophysical Research Consortium. The University of Washington and the University of Chicago have a combined 63% share and a proportionate amount of viewing time.

It was a bargain to boot. The $11-million facility would have cost about four times that much without the novel design. Margon points out that only $3.7 million of the total cost was covered by the federal government; other sources furnished the rest, and the mirror itself, 3.5 meters in diameter and valued at $1.5 million, was donated. The project reflects what he calls a "new order" in the funding of major academic research facilities in the face of waning government resources. "Universities are having to find innovative ways to adapt," he says. Margon further points out that the non-federal funding allows the operators of the Apache Point Telescope greater autonomy and flexibility in setting priorities and scheduling use.

Margon observes that the telescope will fill an important niche between the orbiting Hubble Space Telescope and the 10-meter Keck telescope in Hawaii, the largest on earth. "The Hubble's mirror was limited by the size of the space shuttle that launched it, and, as such, has only half the light-collecting ability of ours, and the Hubble is extremely expensive to operate," says Margon. "The Keck has 20 times the light-collecting ability of the Hubble and 10 times that of ours, so they're not going to be looking at anything but the faintest fuzzballs at the edge of the universe. That leaves us free to explore many important problems involving less distant objects up to 100 million times too faint to see with the naked eye."

The Apache Point Telescope's remote operation means that projects can be tailored in ways the would be impossible with large scopes, which lump a researcher's observing time into three or four nights. Many astronomical events happen on a scale of weeks and months, such as binary stars orbiting one another, or a star interacting with a black hole. Such events may be better studied with the Apache Point facility. As an example, Princeton astronomer Ed Turner uses the Apache Point Telescope to study the light variations from quasars that are split, or lensed, around intervening objects, providing a new way to measure distance. Without the remote and flexible features of the Apache Point facility, Turner couldn't obtain the repeated observations he needs, nor could he afford to leave Princeton often enough to finish the job.

The new Apache Point Telescope is more flexible, too. If a star explodes somewhere in the northern sky, the new scope could zoom in immediately and remain on the star for as long as desired. Moreover, different light-sensing instruments can be interchanged in minutes, allowing different features of the star to be observed. "At other large telescopes," Margon says, "you'd be stuck using one light detector for the entire night."

New findings from Apache Point are revealing details of an ever-more complex and peculiar menagerie of heavenly bodies, from dwarf galaxies and quasars to black holes. In the future, exotic new optics may help researchers locate planets orbiting around other suns.

  1. "The Golden Age of Astronomy," Bill Dietrich, The Seattle Times, August 6, 1995, p.1.
  2. "Mountain comes to astronomers, via Apache Pt. telescope," University Week, May 12, 1994, p. 8.

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