Chile, Argentina will be under the narrow, 6,000-mile long band that will experience a total eclipse when the Moon will completely block the Sun.
Darkness will prevail over large parts of Chile and Argentina turning the day into night. As a total eclipse of the Sun plunges a vast swath of the southern Pacific and the cone of South America into darkness.
According to Chilean astronomers, the breathtaking natural phenomenon will begin at 13:01 (17:01 GMT) in the Pacific Ocean and a 95 mile (150 kilometer)-wide band of total darkness is set to reach Chile's coast 4.38 pm (2038 GMT), then cross into southeastern Argentina.
People in some areas under the path of the eclipse will experience more than two minutes of total darkness, the Chilean Foundation of Astronomy says.
"There's a lot of expectation. This is a historic event in the region," said Catalina Henriquez, who runs an astrotourism agency in Vicuna, a town 280 miles north of Santiago renowned for clear skies that have made it Chile's "astronomy capital".
An estimated 300,000 tourists have flocked to the region where dryness, crystal-clear air and low light pollution has created a stargazers' paradise.
Thousands of people have descended on the nearby town of La Higuera, located on the so-called "path of totality," where the eclipse is predicted to last longest, around 2 minutes and 36 seconds.
Chilean President Sebastian Pinera and several members of his cabinet will watch the event from the La Silla Observatory, on a mountain peak towering 2,400 meters over the Atacama Desert, operated by the European Southern Observatory.
Solar eclipses happen when the Sun, the Moon and Earth line up, allowing the Moon to cast its shadow on Earth.
The next total eclipse will be visible in southern Chile on December 14, 2020.
Agence France-Presse