The Sciences

On Top of Kitt Peak

Seven thousand feet above Arizona's saguaro forests, a unique gathering of observatories probe the universe's darkest secrets

By Corey S PowellMay 1, 2005 5:00 AM


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The journey from Earth to astronomy heaven takes just 20 minutes. A modest turnoff from State Route 86, a lightly trafficked slash of asphalt cutting through the Tohono O’odham reservation, begins the constantly rising path to Kitt Peak National Observatory. Each twist of the 12-mile drive shifts the balance between terrestrial and celestial, as the baked, brown Sonoran Desert takes on atmospheric blue overtones and the sky opens wide. Then they pop into view, first in ones and twos and then en masse: the domes, dishes, and strange sheds that house the 23 telescopes of Kitt Peak, the largest, most diverse gathering of astronomical instruments in the world.

Here Vera Rubin and Kent Ford of the Carnegie Institution of Washington cataloged the rotations of spiral galaxies and discovered that the universe is full of invisible dark matter. Here Robert Kirschner of Harvard University and his colleagues found an enormous void of starless space, 150 million light-years across, while another team uncovered evidence of a black hole that packs the mass of 2 billion suns into a space no larger than our solar system.

During the day, a displaced calm hangs over the site. Signs outside the two dormitories issue a terse warning: “Day sleepers—quiet, please.” Only a few instruments can operate in the blazing Arizona brightness. The McMath-Pierce Solar Telescope, the largest of its kind, burrows 150 feet deep into the ground to provide a cool, clear view of the sun. The 25-meter (82-foot) dish of the Very Long Baseline Array telescope operates in tandem with nine identical ones around the world to form a 5,000-mile-wide radio antenna; light does not interfere with this work.

After sunset the sky explodes with stars, and Kitt Peak springs to life. Every instrument plays its role. The oldest telescope here, the 0.9-meter Spacewatch, predates the observatory complex by 36 years (it was moved here in 1963), yet it remains an active player. James Scotti of the University of Arizona uses it to catalog asteroids that pass uncomfortably close to home, searching for the one that might be headed toward a catastrophic impact. The newest telescope, the boxy WIYN 3.5 meter, inaugurated in 1994, serves as a test bed of new astronomical technologies. Steve Howell of the National Optical Astronomy Observatory has outfitted it with an experimental silicon chip that electronically removes distortion, which should allow him to track the subtle shadow of a Jupiter-size planet passing in front of its parent star in another solar system far, far away.

But not tonight. High winds and sheets of cloud roll in, severing Kitt Peak’s connection to the sky. Howell shakes his head at the blobby images on his computer screen. He will have to wait until his next observing run. Fortunately, heaven can wait.

Fast file: Kitt Peak National Observatory

Elevation: 6,875 feet

Area: 200 acres

Location: Within the Tohono O’odham Nation, 56 miles southwest of Tucson

Clear skies: 72 percent of the time

Scientist population: More than 500 researchers a year work at Kitt Peak

Year founded: 1957 (site selected), 1960 (first telescope installed)

Origin of name: Surveyor George Roskruge named it after his sister, Philippa Kitt; the Tohono O’odham call it Ioligam (meaning “manzanita,” a shrub).

1. McMath-Pierce Solar Telescope Sunlight reflects down a 500-foot shaft to the main mirror. The path is lined with 4.7 miles of pipes carrying chilled water and antifreeze. Light then bounces to various instruments. These have enabled scientists to monitor the sun’s magnetic activity and to find water vapor in its atmosphere.

2. SOLIS/Kitt Peak Vacuum Telescope After 29 years of solar imaging, the vacuum telescope was decommissioned in 2002. A newly installed suite of instruments, called SOLIS, is monitoring the sun’s long-term variability, mapping its magnetism, and studying how it stores and releases energy. This information will clarify the sun’s role in climate change.

optical telescope/new technology/solar system

3. Razdow telescope A companion to the Kitt Peak Vacuum and McMath-Pierce Solar telescopes, the tiny Razdow used to monitor sky conditions and warn observers inside the other two facilities of conditions that would degrade their observations. Now obsolete, it will soon be replaced with a solar telescope for public education.

optical telescope/solar system

4. WHAM telescope The Wisconsin Hydrogen-Alpha Mapping telescope focuses on the light emitted by hot hydrogen gas. The data it gathers are helping to produce a detailed map of temperatures and densities throughout the Milky Way. Astronomers at the University of Wisconsin at Madison operate WHAM by remote control.

optical telescope/new technology/deep space

5. RCT Consortium telescope The Robotically Controlled Telescope was built in 1965 as a test bed for future orbiting space telescopes. In its updated form, it receives e-mail requests from astronomers and automatically executes the observations, searching for planets around other stars and monitoring the flickering of gas falling into black holes.

optical telescope/new technology/deep space

6. KPNO 2.1-meter telescope Once the giant of Kitt Peak, the 2.1 meter is the mountain’s fourth-largest optical telescope. It is primarily used to study infrared rays—slightly longer than visible light—from young stars and distant galaxies. It also revealed the first instance of gravitational lensing, in which gravity focuses the light of a distant object.

optical telescope/new technology/deep space

7. Coudé Feed Tower Complementing the 2.1 meter, the Coudé Feed shunted a second stream of starlight to the Coudé spectrograph, a device that splits the light into its component wavelengths. That analysis enabled researchers to measure the rotation and subtle pulsation of stars, key information for understanding stellar evolution.

optical telescope/deep space

8. WIYN 0.9-meter telescope A consortium of three universities (Wisconsin, Indiana, and Yale) and one institution (National Optical Astronomy Observatory) recently upgraded Kitt Peak’s first research telescope, which began operating in 1962. WIYN’s wide, one-degree field of view facilitates the study of nebulas, galaxies, and galaxy clusters.

optical telescope/new technology/deep space/solar system

9. WIYN 3.5-meter telescope Everything here is about control: Cool air regulates the mirror’s temperature, actuators adjust its shape, and a new wide-field camera will remove distortion. Such innovations allow studies of comets, quasars, and infant galaxies with a detail never before possible from the ground.

optical telescope/new technology/deep space/solar system

Courtesy of Jack Kennedy/NOAO/ AURA/NSF


SARA Observatory

In 1995 the Southeastern Association for Research in Astronomy merged pieces of two older instruments into this one. Some of the SARA telescope’s time is devoted to undergraduate astronomy students, who work on internships here. At other times, professionals use it to monitor the flickering of variable stars.

optical telescope/deep space

Courtesy of Jack Kennedy/NOAO/ AURA/NSF

13. ETC/RMT The Explosive Transient Camera/Rapidly Moving Telescope is something of a ghost observatory. Inaugurated in 1991 to search for flashes of light from gamma-ray bursts—enigmatic explosions mostly seen in very distant galaxies—it never found one and was eventually shut down. Only a shed marks its former location.

optical telescope/deep space

14. Spacewatch 1.8-meter telescope The larger Spacewatch facility, completed just five years ago, follows up on interesting objects spotted by its junior partner. The 72-inch mirror, scavenged from the Multiple Mirror Telescope on nearby Mount Hopkins, makes it the world’s largest telescope devoted exclusively to searching for comets and asteroids.

optical telescope/new technology/solar system

15. Spacewatch 0.9-meter telescope This storied instrument moved here from the University of Arizona when urban growth made its original location unsuitable. It surveys the sky for asteroids, detecting about 4,000 per night. The goal is to find all the 1,500 or so sizable ones passing close enough to Earth to cause a devastating impact.

optical telescope/new technology/solar system

16. Super-LOTIS Picking up where the ETC/RMT left off, the Livermore Optical Transient Imaging System is hunting for the visible-light glow that lingers after the more energetic radiation from a gamma-ray burst has faded. The bursts are believed to be massive stars collapsing into black holes, among the biggest fireworks in the cosmos.

optical telescope/new technology/solar system

17. HAT-1 In 2000 Gáspár Bakos, a college student in Hungary, dreamed up a way to catch any rapid astronomical events that normal telescopes miss. His Hungarian Automated Telescope swept the sky with a Nikon telephoto lens, collecting data on anything that changes. It was recently relocated to nearby Mount Hopkins.

optical telescope/deep space

18. Bok telescope The unusual building—said to resemble a can of bug spray—houses a versatile telescope that has contributed to studies of interacting double stars, quasars, and the central regions of galaxies. The Bok has also collected data on the mysterious Kuiper belt objects, a group of frozen bodies that includes Pluto.

optical telescope/deep space/solar system

19. KPNO Mayall telescope The Mayall’s landmark 200-foot-tall structure signifies an older design than the squat WIYN. Its huge 15-ton mirror excels at light-sensitive work, such as tracking distant supernovas to determine how the universe’s expansion is changing over time.

optical telescope/new technology/deep space/solar system

20. Steward Observatory This aluminum dish, built atop an Army tank turret, gathers high-frequency radio waves. Work here has shown that carbon monoxide in nebulas helps trigger star formation; newer studies are uncovering the complex organic chemistry of space.

radio telescope/deep space

21. MDM Observatory 1.3-meter telescope In 1975 the University of Michigan teamed with Dartmouth and MIT to move its 1.3-meter telescope from Ann Arbor to Kitt Peak. MIT has left the partnership, replaced by Ohio State University and Columbia University. Multiple ownership helps more students and faculty members get precious telescope time.

optical telescope/deep space/solar system

22. MDM Observatory 2.4-meter telescope The larger MDM telescope began operation in 1986. The two instruments have performed a number of long-term surveys, among them a census of how galaxies are distributed through space. Such studies of large-scale structure are helping cosmologists refine their picture of the early universe and its origin.

optical telescope/new technology/deep space

23. Very Long Baseline Array Nine matching radio telescopes, from Hawaii to the Virgin Islands, link with this one to produce the sharpest-ever views of the universe. The array probes torrid gas around black holes; it also monitors our own planet, measuring shifts in Earth’s crust as small as one-fifth of an inch.

radio telescope/new technology/deep space/solar system

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