France, Aug. 12 -- "Standing within the shadow of the Moon," says Fred Espenak - a Nasa scientist known as "Mr Eclipse" - gives us "a rare opportunity to gaze directly at the halo of million-degree plasma surrounding our star."

The solar corona - consisting of tongues of fire stretching thousands of kilometres from the surface of the Sun - "is revealed to the naked eye only during the brief seconds when the Moon completely blocks the brilliant disc of the Sun," he explains. Total solar eclipse seen from the NASA Glenn Research Center in Cleveland, Ohio, 8 April, 2024.

Spanish authorities are expected a staggering 6 million people to view Wednesday's eclipse, and have designated some 660 official viewing sites, along with parking and cam...