When this year's Leonid meteor shower peaks on Nov. 17-18, Colorado skywatchers may be treated to the best show in years, according to Francisco Salas of CU-Boulder's Fiske Planetarium.
The Leonid meteors are part of the debris trail expelled by comet Tempel-Tuttle in its 33-year orbit around the sun. The Earth happens to pass through this trail of debris each November.
Most meteors range in size from that of a pea to a small pebble, said Salas. These particles slam into the upper reaches of the planet's atmosphere, vaporizing at an altitude ranging from 100 miles to 200 miles.
Meteors in a shower appear to radiate from a specific area in the sky --called a radiant -- as Earth crosses the cometary debris trail. The effect is similar to the way that railroad tracks seem to come from a single point in the distance. The radiant for this shower lies in the constellation Leo, and therefore the shower is called the Leonid meteor shower.
Salas said that scientists are predicting a meteor storm of 5,000 to 10, 000 meteors per hour this year, at its peak. This year's higher than usual level of activity occurs because the Earth will enter a part of the cometary debris trail that is especially thick. The more debris the planet passes through, the better the show for skywatchers.
Meteor showers are some of the best free entertainment that Mother Nature can offer, Salas said. It will, however, take some dedication on the part of observers to enjoy the full force of this year's show.
This time of year, the constellation Leo rises in the east around 3 a.m. "But at that time," said Salas, "it is too close to the horizon for easy viewing." If skywatchers wait until about an hour before sunrise, Leo, "the lion," will be high enough in the sky that city lights in the east will not significantly affect viewing.
"About five o'clock in the morning, skywatchers should look all the way to the zenith, which is the very top of the sky overhead, and then look slightly south about the width of your four fingers as you extend your hand, for a group of stars in the shape of a backward question mark," he said.
This shape forms the head of the lion, said Salas, and is dominated by two very bright stars. The meteors should appear to radiate from that entire region of the constellation. "If you are unable to find the constellation, just look straight up and wait a few seconds - the show will be hard to miss," he said.
The important thing is to get away from city lights, which make it more difficult to see celestial events. "Flagstaff or North Boulder are nearby locales for viewing that are nice and dark," he said.
Fortunately, the moon will be below the eastern horizon at the time, and should not impede viewing. "If the weather is good, we should have a great show this year," Salas said. "Just remember to bring a blanket and some hot chocolate or coffee to stay warm."
According to Salas, the best way to view a meteor shower is with the naked eye, not with a telescope or binoculars, which limit the field of view.
Also, the more dense part of the debris trail has a greater variety of particles. "If we are lucky we will see some bollides, which streak across the sky for three to five seconds. You can actually see some color in them as the elements they are made of give off specific colors of light."
If potential meteor watchers are reluctant to get up so early to see the Leonids this year, there's always next year, said Salas. Scientists are predicting another great show for 2002 as well.
For more information contact Fiske Planetarium at (303) 492-5002 or visit the Web site at .