Get ready for heavenly light show

It hasn't appeared in our sky for nearly a quarter-century, but during the pre-dawn hours of Thursday, May 6, stargazers will have a chance to see pieces of the most famous of celestial visitors: Halley's comet. On that morning, sky watchers far from city lights will be treated to the Eta Aquarid meteor shower.

Meteors, or shooting stars, are specks of interplanetary dust hardly larger than a sand grain that encounter the Earth at speeds of tens of miles per second. As one of these slams into our atmosphere, it heats up and causes the neighboring atmospheric gases to glow. It is this fiery demise that we see as a meteor.

The meteors of the Eta Aquarid shower fell off the most famous of all comets: Halley's comet. They tend to collide with our atmosphere almost head on at speeds up to 42 miles per second, and the brighter ones can often show a yellowish color.

These meteors will appear all around the sky, but you can tell if one is part of the Eta Aquarid shower by tracing its path backward. If it appears to come from the direction of Aquarius, low in the east-southeastern sky before dawn, it is almost certainly associated with this shower. If it doesn't, it's what astronomers call a "sporadic" meteor.

Though historical records suggest that stargazers have seen the Eta Aquarids since about 74 B.C., the shower was not officially "discovered" until 1870 by Lt. Col. G. L. Tupman.

To view the celestial show, head away from city lights where the sky is dark and clear. Under ideal conditions, stargazers may see as many as 40 or 50 meteors every hour, coming from the eastern sky. The best times for viewing will be between midnight and the first light of dawn.

The best part is that all you need to view the shower are your eyes, a lawn chair or sleeping bag and some warm clothing. Absolutely no binoculars or telescopes are needed to view the shower - they would produce much too narrow a field of view to see the all-sky show, though you may wish to have binoculars handy to check out the persistent smoke trails left behind by some of the meteors.