Astronomy:

Visiting The Great Observatories

KPNO, Arizona:

This is the Kitt Peak National Observatory: America's "Telescope Town." The nearly 6900 ft (3100 m) mountain-top is about 55 miles southwest of Tucson, Arizona, in the Tohono O'Odham Nation (a Native American culture). The mountain is a sacred place to these people, and the National Optical Astronomy Observatory (NOAO) does its best to be a good tenant. The mountain is covered with an amazing array of large instruments, looking in every part of the spectrum. There are 11 major optical and radio telescopes sitting up here - it really is like a pilgrimage to the great astronomical shrine of the ages. Visiting astronomers sleep in dormitories, far from city lights and signs of civilization. The nearest restaurant is a long drive down the mountain.

The mountain has always been a sacred site for the Anasazi, a native people whose culture spans many of the modern American Indian tribes. A splendid mosaic artwork welcomes visitors to this spot where ancient skywatchers and modern science meet on an ancient peak. A telescope main mirror template rests at the edge of the parking lot (right), looking like a giant Lifesaver candy, and reminding vistors just how huge these scopes really are.

This is the most fascinating piece of giant modern art I've ever seen: it is the unique McMath-Pierce Solar Telescope - the largest Sun-watcher on Earth. If you want to study sunspots, this is the hot ticket. It is also the largest unobstructed telescope on Earth - that is, one without a smaller secondary mirror partially blocking the main light collection mirror. So, you've got a whopping 1.6 meters (62 in) of solar-scamming aperature. I still think the whole thing looks like something I would have built from old cardboard boxes when I was a kid - only 50 meters taller...

This is the "Little Rascal," a scope only 0.9 meters (36 in) in size, and the oldest working scope on the mountain. Astronomers use the attached digital imaging system (right) to observe galaxy clusters, variable stars (which change in brightness), and planetary nebula. The row of square shutter doors surrounding the lower half of the dome provide increased airflow, helping steady astronomical images.