The long-ballyhooed Leonid meteors of 1998 finally arrived yesterday, and they astonished sky-watchers from Maryland to Australia with brilliant displays of light and color.

Although the display was more a heavy meteor "shower" than the hoped-for "storm," it was more than enough to delight most observers. Where the clouds parted, they reported seeing hundreds, even thousands of shooting stars per hour and colorful fireballs bright enough to shine through clouds and cast shadows.

In Iowa, Mark Mikutis declared it "simply unbelievable."

In an e-mail message to Sky & Telescope magazine's Leonid Web page, he reported seeing up to 6 meteors per minute. Fantastic fireballs illuminating the horizons. Geese on the lake going nuts. I've never seen anything like this before in my life!!!"

Astronomers expected some heightened meteor activity would continue into the early hours today.

Brian G. Marsden, director of the International Astronomical Union's Central Bureau for Astronomical Telegrams in Cambridge, Mass., said early reports from around the globe indicated "substantial Leonid activity earlier than expected, with high proportion of very bright fireballs, some brighter than magnitude -8, with enduring trains [similar to jet contrails]."

A magnitude -8 object is about 40 times brighter than the planet Venus, a magnitude -4.

The most impressive display, Marsden said, was reported from Las Palmas, the Canary Islands, off northwestern Africa. Observers there saw meteors flash across the sky at rates of from 1,000 to 2,000 per hour at about 3: 30 a.m. Tuesday local time (10: 30 p.m. Monday night EST).

Francisco A. Rodriguez Ramirez, in an e-mail message from the Canaries to Sky & Telescope, said the show began as soon as the constellation Leo -- the region of the sky from which the Leonids seem to radiate -- rose above the eastern horizon.

"Fireballs crossed the whole sky," he said. "Some reached magnitudes of -9. Most left a train of several seconds, and the most brilliant with trains 5 minutes visually. For moments we were not able to record our count because even in intervals of 2 seconds we saw up to 6 meteors."

The Leonid meteor shower occurs every year around this time, with typical displays of 10 or 15 an hour as the Earth passes through the dust trail of the periodic Comet Tempel-Tuttle.

But every 33 years or so, around the time of the comet's return to the inner solar system, the number of Leonid meteors increases sharply. In 1966, the shower became a storm, with as many as 150,000 meteors an hour.

Yesterday, sky-watchers in the United States had a great show, at least where the sky was clear.

Between 3 a.m. and 4 a.m. CST in Illinois, Christopher Beau Dodson counted more than 100 meteors, including 50 fireballs. "The fireballs left streaks of green, yellow, pink and red. Two lit the sky so one could see the surrounding countryside," he told Sky & Telescope.

The meteors were even visible where gaps appeared in the generally cloudy sky over Maryland. Several early risers and late-shift workers in Baltimore and Washington reported seeing as many as 15 bright, vivid meteors through fleeting breaks in the clouds.

Stephen P. Maran, an astronomer at the Goddard Space Flight Center, was up at 2: 15 a.m. and managed to see four Leonids in the bright sky above his suburban Chevy Chase home.

"I saw one that was extraordinary," he said. "It left a luminous trail that persisted for 30 seconds. That particular part of the sky was partly cloudy, so I was seeing the meteor and its train through the cloud, and it was still bright."

The shooting stars are tiny bits of metal or stone expelled from the comet as the sun's warmth boils away the ice that has held them in place, perhaps since the birth of the solar system 4.5 billion years ago.

Most are no bigger than grains of sand or pebbles. But the Earth moves through them at speeds greater than 155,000 mph. With that sort of energy, they burn up high in the Earth's atmosphere, heating the surrounding gas molecules until they glow.

More than 500 satellites orbiting outside the atmosphere were at some risk from collisions. But there were no immediate reports of damage.

Most satellite operators took precautions, reducing power or turning their spacecraft so they presented the slimmest possible profile to the oncoming meteor stream.

Scientists had predicted the Leonid shower would peak at about 2 p.m. EST yesterday. They forecast 200 to 5,000 meteors an hour, with the best viewing in East Asia, on the night-darkened side of the planet.

Astronomers were spread out from Mongolia to Australia, toting state-of-the-art equipment to record and measure the shower.

In one of the most ambitious efforts, two U.S. planes taking off from Japan aimed a battery of instruments at the sky to produce high-resolution stereoscopic views of the incoming meteors.

NASA spokesman Don Savage said the crews reported seeing about 1,000 meteors an hour.

Scientists on board hoped to learn something about the composition and chemistry of the cometary dust as it burned up in the upper atmosphere.

"This may help us understand how extraterrestrial materials helped create the conditions on Earth necessary for the origin of life," said Peter Jenniskens, principal investigator for the Search for Extraterrestrial Life Institute in California.

Elsewhere, observers on the ground had plenty to see.

M. Langbroek, a member of a Dutch expedition observing from central China, reported seeing 489 Leonids in 3 1/2 hours, including "a spectacular number of fireballs."

In England, Stuart Atkinson could see the meteors through low, misty clouds, "making it look like there's a WW2 artillery bombardment going on. Unbelieveable, truly spectacular."

Watching in New Jersey, Fred Schaaf said three of the 54 Leonids he saw cast shadows. "One of the brightest flashed off and on like lightning," his e-mail message to Sky & Telescope said.

Roberta Burns wrote from Kentucky that several fireballs there glowed bright green and violet. "Never before have I seen a meteor shower that made me scream and squeal with such delight," she said.

Leonid reports by Sky & Telescope can be found at www. skypub.com/sights/meteors/ leonids/98firstreports.html

Pub Date: 11/18/98