Cloud Cover Threatens to Eclipse Eclipse : Astronomy: Dense marine layer likely to impede view from Southland coast. Local observers are advised to head at least 10 miles inland for a clear look at the rare sight.

A rare partial eclipse of the sun will occur this morning over Orange County, but weather forecasters said that residents in the coastal areas are not likely to see much because of clouds.

Only inland areas of Orange County are likely to have skies clear enough this morning for the eclipse to be visible, according to WeatherData Inc., which provides weather data for The Times.

“There’s going to be low-lying clouds and patchy fog around the coast at the time of the eclipse,” said WeatherData meteorologist Michael Schlesinger. “The best thing for people to do, if they’re trying to see the eclipse, is to head inland about 10 miles. There will still be some clouds, but there will be a better chance for seeing the sun.”

The eclipse, which will completely block out the sun over parts of Mexico and Hawaii, will start at 10:12 a.m., peak at 11:28 and end at 12:48 p.m. In the Orange County area, there will be about a 70% eclipse at the peak.

Health and safety officials stressed that even if the eclipse is obscured by cloud cover, no one should attempt to look at the sun--even briefly--without special glasses or viewing equipment. Even at the height of the eclipse, the sun’s rays can permanently damage the retina in just a few seconds, and such damage is irreversible.

If you don’t have access to special glasses, you can construct a pinhole camera with just two pieces of cardboard to provide safe viewing. Punch a one-eighth-inch hole in one card, and allow sunlight to shine through it and fall on the second, held 2 to 3 feet behind it.

Or, you can punch a small hole in one end of a cardboard box and allow the sun’s image to be projected onto the opposite end. Hold the box over your head to watch.

Under no circumstances should you attempt to view the eclipse through conventional sunglasses, smoked glass or exposed photographic film, experts say. Irregularities in the coatings can allow damaging light rays to pass through.

Welders’ goggles or welders’ glass with a rating of at least 14 can be used safely, however.

An eclipse occurs when the moon’s passage between the sun and the Earth is at a rare positioning--one that temporarily shadows part of the Earth.

The eclipse has produced lively interest in Orange County.

“It’s been wild,” said Bill Hartong, president of Oceanview Instruments in Newport Beach. “This morning (Wednesday), we got a special order in of Mylar glasses for people to use in viewing the eclipse. That shipment of 1,000 glasses came in at 10:30 (a.m.), and by 1:30 (p.m.), every one of them was gone.”

Eclipse enthusiasts who flew to Hawaii, where the moon will block 100% of the sun for four minutes, may be disappointed. It was raining heavily over much of the Big Island of Hawaii on Wednesday.

Schlesinger of WeatherData said the skies over the islands will be partly cloudy this morning, meaning that the thousands of tourists who traveled to Hawaii to view the spectacle might be thwarted by a persistent cloud cover.

Astronomers who planned to view the eclipse with telescopes atop the Mauna Kea volcano may be stymied not only by the cloud cover, but also by dust and ash injected into the upper atmosphere by the recent eruption of Mt. Pinatubo in the Philippines.

The worst viewing of all may occur in inland Mexico and Central America, where the rainy season is in full swing. Tourists and scientists there may see little more than a six-minute soggy blackness with a biting 50-degree temperature plunge to boot, forecasters say.

The alignment of the Earth, moon and sun will also produce unusually high tides in Southern California. The high tide will top out today at 7.8 feet at 9:41 p.m. in San Diego. It is the highest tide this year and there will be no higher tides for the rest of this century.

In Los Angeles and Orange counties, tides will average about 7.2 feet at 9:28. Property damage could occur in low-lying areas along the coast if high waves accompany the tides, but such waves are not forecast.

Times science writer Lee Dye, in Hawaii to cover the eclipse, contributed to this story.