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A diagram shows the projected path of this Sunday's total solar eclipse.

Total Solar Eclipse Sunday—Most Remote of the Century?

Eclipse visible to a lucky few on Pacific isles such as Easter Island.

On Sunday the moon's shadow will sweep across Earth during one of the most remote total solar eclipses of the century.

The eclipse will be visible only along a narrow, 155-mile-wide (250-kilometer-wide) band that will cross the Pacific Ocean, starting north of New Zealand at 2:15 p.m. ET and ending in the southernmost tip of South America at 4:52 p.m. ET.

As it crosses the Pacific, the total solar eclipse will also darken a handful of remote South Pacific islands, including Easter Island (Isla de Pascua)—about 2,500 miles (4,000 kilometers) west of Chile. (See a picture of stars over the moai, the famous stone statues of Easter Island.)

The eclipse will last the longest—5 minutes, 20 seconds—over open Pacific waters at 3:33 p.m. ET.

"Since much of the pathway is over open ocean, this will be one of the least observed eclipses ever," said eclipse expert and National Geographic grantee Jay Pasachoff, Field Memorial Professor at Williams College in Massachusetts. (The National Geographic Society owns National Geographic News.)

Eclipse chaser and astronomer Alan Dyer, of the Telus World of Science-Calgary in Alberta, agreed.

"The most noteworthy aspect of this eclipse is how little land it crosses and the sparse population areas in the path—unlike last year's eclipse, which passed over several huge cities in China," he said. (Read "Total Solar Eclipse Was Record Blackout." [2009])

"Tens of millions were able to see that eclipse. Only a few thousand will see this one."

Eclipse Chasers Seeking Island Getaways

During a total solar eclipse, the moon passes between Earth and the sun, casting a circular shadow over the planet. (See a picture of a solar eclipse as seen from space.)

On the ground, viewers in the full shadow's path—aka the path of totality—see the moon completely cover the sun's disk for several minutes. Only the sun's faint upper atmosphere, or corona, remains visible.

Elsewhere, sky-watchers can see a partial eclipse, where the moon covers just part of the sun.

Total solar eclipses can happen up to five times a year, although each year is different due to variations in the positions of Earth, the moon, and the sun over time. In 2011, for example, there won't be a total solar eclipse, only partial ones.

For the 2010 total solar eclipse, people in a broad track thousands of miles wide will see a partial eclipse from the South Pacific Basin and South American mainland.

Meanwhile, throngs of eclipse chasers from around the world have been gathering at exotic Polynesian locales to experience the rare sight of full totality.

In addition to Easter Island, a Chilean territory, the total solar eclipse will envelop the Cook Islands, an autonomous region of New Zealand, and the Tuamotus Archipelago of French Polynesia. (See pictures of island getaways.)

Solar Eclipse "Twilight" Part of the Spectacle

Observing from Easter Island, Williams College's Pasachoff will be witnessing his 51st solar eclipse. (Take a mysterious-places quiz.)

Pasachoff is among the eclipse chasers who hope to use the event to glean valuable data about the sun's corona, which normally can't be observed from the ground. In fact, parts of the corona seen during eclipses are invisible even to sun-watching satellites.

"On the days of eclipses—and only on those days—can we supply high-quality images of the inner and middle corona that fill in the gaps in spacecraft coverage," Pasachoff said.

"We can learn about the sun's magnetic field and the relation of the sun and the Earth by studying eclipses."

Telus World of Science's Dyer, meanwhile, will be positioning himself on a remote atoll near Tahiti to simply enjoy the spectacle.

For him, a big part of the event is observing dramatic changes in the local environment during the brief few minutes before and after totality.

"The twilight horizon colors, weird sharp shadows, and other fleeting phenomena [surrounding the eclipse] are so immersive and overwhelming," Dyer said.

"Being on a flat atoll should afford us a wonderful view of the horizon all around us—the changing colors of the sky can be just as amazing as the sight of the eclipsed sun itself."