It’s been nearly two years since the “Great American Eclipse”. Millions compressed into a 70-mile (110-kilometer) wide path of totality extending from coast to coast, where the Moon absorbed out the Sun to usher in spontaneous nightfall. It was a planetary cavalcade, unlike anything most had seen.
This Tuesday, Earth will again find itself the backdrop of the Moon’s shadow, but this time, basking in the lunar umbra won’t be so easy. Though the path of totality spans 6,000 miles (9,600 kilometers), most of it is over the remote South Pacific.
Only a narrow zone in Chile and Argentina will witness totality before sunset – weather allowing.
This time around will be a higher-stakes but higher-reward event. It’s winter in the Southern Hemisphere, and Mother Nature’s caprice manifests itself in the chaotic conditions of the Andes Mountains.
La Serena – a coastal city of 200,000 about 250 miles (400 kilometers) north of Santiago and the first community to be plunged into darkness – is frequently buried beneath a deck of marine stratus clouds.
Making matters more complicated is the low altitude of the Sun. Since totality strikes at 4:38 pm local time – just one hour, 18 minutes before sunset – the solar disk will hover a mere 13 degrees above the northwest horizon as the Moon blocks its light.
That means even distant clouds could spoil the show. During the 2017 eclipse, the Sun was 60 degrees high, so the only clouds that mattered were the those directly above. The eclipse in Chile will be much trickier.