Chabot astronomer Ryan Diduck said few comets - frozen masses that travel around the sun in an elliptical orbit - can be seen with the naked eye. "Most comets that are flying through our solar system are so small or so far away you can't see them," Diduck said.

Visible comets pass through outer space about once every decade. In 1975, comet West dazzled amateur stargazers with two distinct tails, a blue plasma tail made up of gases and a white tail made up of microscopic dust particles. Astronomers lauded the arrival of Halley's comet in 1986, but Diduck said many people were disappointed because it appeared so small and faint. Hale-Bopp is 1,000 times brighter than Halley's at the same distance, astronomers said. Hale and Thomas Bopp discovered the comet independently, in New Mexico and Arizona.

Comet NEAT, which stands for Near Earth Asteroid Tracking, is already visible in the eastern sky and will be until the end of the month. Diduck said NEAT is now low and hidden by the East Bay hills.

"It will be rising higher in the sky as we go through the month, but the downside is it will also be fading toward the end of the month," he said.

The LINEAR comet, named after the Lincoln Near Earth Asteroid Research project that discovered it, will join NEAT mid-month. Although both are visible to the naked eye, astronomers say using binoculars will aid in viewing them. A third comet, Bradfield, came and went earlier this month.

Hale will speak today and Saturday during Chabot's Our Sky Tonight planetarium show at 6 p.m. Telescope viewing on the Chabot deck will follow. Tickets to the show are $6 adults, $5 for youth and seniors. Chabot Space and Science Center is at 10000 Skyline Boulevard, Oakland. For information please contact (510) 336-7300.

The Oakland Tribune: Cityside
Leanne McLaughlin, Managing Editor
(510) 208-6447
(510) 208-6477 Fax
lmclaughlin@angnewspapers.com Email