Visit to the Planetarium

Took in two shows at the University of Arizona planetarium last night. The first featured the telescopes on a 14,000 ft peak in Hawaii. The second showed some of the sights that can be seen in the Arizona sky, and explained how best to see them.

As with any hour-long presentation, I get restless when they include a lot of information I consider trivial. However, there are always one or two tidbits to be gleaned from even the most long-winded program.

Some of the tidbits:

•The number of degrees the north star is off the horizon equals your degrees of latitude. So, at the 47th parallel (northern Minnesota), the North Star is 47 degrees off the horizon. In Tucson, the North Star is 33 degrees off the horizon. It is easy to measure the degrees by extending your arm. The distance between the tip of your thumb and the tip of your pinky finger on an open hand is 20 degrees. A fist is roughly 10 degrees. Two fingers is 5 degrees, and so on.

•An observatory at the equator can see the entire sky through the course of a year. An observatory at the north pole only sees one-half of the sky.

•The star which forms the bend in the handle of the Big Dipper is actually a small cluster of stars. You can see two through binoculars, and six through a small telescope.

•The beautiful pictures of nebula that have come from the Hubble telescope are the result of very long photographic exposures--sometimes hours. The light from these nebula is so faint that the naked eye, even when aided by a powerful telescope, can never really discern the colors that show up so vividly in the pictures.

•Scientists remain quite ignorant about the existence of planets orbiting other stars. They can only detect such planets by sensing the vibration of such stars as they respond to the pull of their orbiting planets. Scientists have found 100 such planets orbiting the stars nearest us. The odds from these meager discoveries suggest that there are billions of planets in our galaxy alone. Then consider that they have counted over 150 billion galaxies so far. The mind boggles.

•Venus is bright in the early evening sky right now. In fact, it was so bright two evenings ago that I assumed it was a weather balloon. I learned last night that it is not.