Thousands of amateur skywatchers and wildlife enthusiasts have converged on Central Africa to watch the moon block out the sun and to see what lions, elephants and other animals do when darkness suddenly falls.
Total solar eclipses occur about once every two years on average, but this one — expected to occur about 9:13 a.m. ET — carries special significance. It's the first eclipse of the new millennium and it coincides with the summer solstice, the longest day of the year.
But if you want to see it firsthand and you're not in Central Africa you're out of luck — at least this time around. A total solar eclipse is visible at a given place on Earth only once every 375 years, so it's unlikely one will ever come to you.
Sweeping Across Africa
The moon's umbral shadow sets out on a 120-mile-wide path that starts in the south Atlantic, sweeps across southern Africa, including Angola, Zambia, Mozambique and the island of Madagascar, and stops at sunset in the Indian Ocean.
Witnesses along the 7,400-mile long track will see several minutes of sudden darkness, the backlit moon and some of the brighter stars.
Poor weather conditions marred the 1999 solar eclipse in Britain, but given Africa's fair weather this time of the year, sky-watchers are expecting perfect visibility.
And wildlife scientists will join the astronomers to complete one of the world's first large-scale studies of how animals behave when day suddenly turns to night during a total solar eclipse. Previously, for example, nocturnal animals have set out to go foraging, and birds have returned to their nests to roost.
Experts expect the mammals most likely to be affected will be bats, hippos, warthogs and baboons.
A partial eclipse will be seen within the much broader path of the moon's penumbral shadow, which includes eastern South America and most of Africa (excluding north Africa).
Although the celestial event has brought a great deal of tourists to Central Africa, it has also brought some concerns.
The celestial gathering has prompted an increased police presence in Zimbabwe, where the government fears an opposition group called the Movement for Democratic Change may seize the opportunity to make a political statement. Law enforcement officials launched a nationwide operation to maintain peace during the eclipse.
Most tourists avoided Angola out of fear of land mines that dot the landscape.