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Astronomy tour

Paul Kohlmiller

The author reflected in a 10-meter array of mirrors used for detecting gamma ray bursts.

Mary Kohlmiller poses on the rim of the Grand Canyon.

A pair of 6.5 meter mirrors are being produced. One mirror is nearly completed. The closer mirror is actually upside down at this time. The mirror construction lab is located under the university's football stadium because the large concrete structure adds stability.


On May 3-10, 2003, my wife and I participated in Sky & Telescope magazine's astronomy tour called Arizona Deep Skies and Deserts.

The tour group consisted of about 40 people. The astronomy expertise level of the group covered a wide area. Some did not own a scope and had never been to a star party. Others were quite advanced amateurs with one participant anxiously waiting delivery of his 14" LX200 GPS. We had a tour guide who had lived almost his entire life in Arizona. Also, Stuart Goldman of Sky & Telescope led many of the astronomical events. We were bussed to virtually every event in a Greyhound-sized bus.

Most of the sky-gazing events (at least 5 out of 6) were conducted while the moon was a factor so it is difficult to say how much darker the skies are in Arizona.

One test for transparency is the ability to see all the stars in Ursa Minor. The dimmest star in the bowl of the little dipper could barely be detected using averted vision. My test is being able to see Kappa and Lambda Leonis without averted vision which I can just barely do from my back yard in Gilroy when those stars are close to the zenith. These stars were visible but not much easier than they are at home.

The weather either curtailed or cancelled 4 of the 6 viewing sessions. The result is that the trip felt like it was more about telescope optics and observatory management than the science of astronomy.

We did a tour of Kitt Peak, located about 50 miles southwest of Tucson. Kitt Peak is the largest observatory in the world in terms of the number of telescopes at one location. We saw the solar telescope and then checked out some other scopes. We had a light supper in the observatory dining room and then they gave us a talk in the visitor center. Besides discussing distances between stars and galaxies, they also handed out a planisphere (that wheel star chart that you know and love) and a pair of high quality binoculars to each participant. They also gave each of us a red light flashlight that we got to keep. Then we split into two groups -- each going to one of the two scopes that still use eyepieces. Our group used a 16-inch Meade LX 200. This was my first time viewing the star cluster Omega Centauri. First we found this object using binoculars. Then the view through the scope filled up the entire field of view. This was also the first time I viewed M51 through a scope where the two galaxies looked like they were in contact with each other.

We were deciding whether our astronomical vacation should be at one of those astronomical B&B's or this tour. The clincher was the opportunity to visit renowned astronomer David Levy (of comet Shoemaker-Levy fame) at his house and check out his observatory. David has about 10 scopes in his observatory. We used 2 of the scopes to view various items: Jupiter, M51, Albireo, M57 (Ring Nebula) and others. David and Wendee Levy were very gracious hosts. David also pointed out some interesting astronomical details such as the variability of Delta Scorpii and the full extent of the Hydra constellation.

There are no observatories (that I know of) at the Grand Canyon. However it was fun to watch the shadows move up the cliffs during sunset. At 2 a.m., a hardy subset (no more than 10) set up a couple of scopes and tried to do some viewing. After about an hour in very cold and windy conditions, half of the group gave up which apparently signaled the clouds to part. Before the sunset there was a short sleet shower (don't say that 3 times fast) which led to a partial rainbow rising out of the canyon.

You can walk into observatory dome after dome and pretty soon they all look alike. At Lowell Observatory's Anderson Mesa site we saw something quite different. The difference was the interferometer located there. This consists of a Y-shaped array of tubes that gather light and precisely merge the light from up to 6 different locations along the array. The light hits 24 mirrors along the way following paths whose total distance must be accurate to 10 microns (soon to be 1 micron). The result is the resolving power of a scope that has a diameter the size of the array (more than 400 meters) although the limiting magnitude is much smaller.

The last astronomical event of this tour was a lecture by Dr. Jeff Hester of Arizona State University. Let me set the scene. We are on the balcony level of a sports bar in Phoenix. The bar is owned by rock and roller Alice Cooper so it's called Cooper's Town. All waitresses wear Cooper-inspired eye makeup. The speaker's Powerpoint slides are projected onto a sheet while three other sheets attempt to cover the window. But Hester is in fine form regardless and his talk, while basic, gave an impressive structure for looking at the universe — from the Big Bang to star formation. If you haven't heard of Dr. Hester, you may have seen the Hubble picture called Pillars of Creation — an image credited to him and his team.


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