Tony Hoffman How to Catch a Glimpse of This Summer's Solar Eclipse Parts of Chile and Argentina, as well as a tiny Pacific island, will briefly lie beneath the Moon's shadow during July 2's total solar eclipse. Here's what you need to know.
Parts of Chile and Argentina, as well as a tiny Pacific island, will briefly lie beneath the Moon's shadow during July 2's total solar eclipse. Here's what you need to know.
If you missed last August's solar eclipse, or caught it and are keen to repeat the experience, you will have another chance to spend some precious minutes under the totally eclipsed Sun this summer.
Granted, the eclipse of July 2 won't be nearly as conveniently placed for North Americans as last year's event, in which the Moon's shadow raced across the United States from Oregon to South Carolina. Most of the action this time will be in South America, namely Chile and Argentina, and no part of the US will witness even a partial eclipse. But it will give some intrepid souls a chance to witness one of nature's grandest spectacles from a distant part of the world.
Total solar eclipses are not unusual—one happens somewhere in the world every year and a half or so. But for every one that passes across highly populated and easily accessible areas, there seem to be two or three that are mostly over open water or remote wilderness. This one is somewhere in between; although the path of totality passes near Buenos Aires, there is a high probability of cloudiness in the area, with about 70 percent cloud cover typical for July. More promising locations lie in central to western Argentina, as well as the Chilean coast near La Serena and the inland Elqui Valley. Also, many cruise-ship eclipse tours will intersect the path of totality, and a couple of more exotic options may also be available to a few adventurers.
The eclipse begins at dawn in the Pacific Ocean, about 1,000 miles to the east of New Zealand's North Island. The Moon's shadow tracks northeastward, threading a path between French Polynesia and Pitcairn Island, at mid-morning plunging tiny Oeno Island into darkness for 2 minutes, 51 seconds. The eclipse reaches its maximum duration of 4 minutes, 33 seconds over the open ocean near the track's northernmost point, some 1,200 miles west of the South American coast and 450 miles north of Rapa Nui (Easter Island). From there the Moon's shadow races to the east-southeast, finally reaching the Chilean coastline in the late afternoon. After the shadow treks across the Andes and through Argentina, totality ends at sunset just short of South America's Atlantic coast.
Only a handful of people will see the eclipse from Oeno (weather permitting), an uninhabited atoll accessible only by permission of the Pitcairn Island Commissioner. Most Pacific eclipse chasers will see the event aboard cruise ships, largely between Pitcairn and Mangareva in French Polynesia, which is relatively accessible.
In addition, at least two chartered LATAM airliners are due to fly into the eclipse path. Sky & Telescope magazine's flight will intercept totality off the Chilean coast, while astronomy professor Glenn Schneider—who has flown on or planned 13 airborne eclipse expeditions—is leading a trip that will fly from Easter Island to fly into the Moon's shadow near the point of maximum eclipse, and by flying in the same direction as the shadow moves, hopes to extend the duration of totality for the passengers up to about 9 minutes.
In late afternoon, the Moon's shadow finally makes landfall again, on the Chilean coast north of La Serena. Most eclipse-goers—several hundred thousand, by some estimates—will be near La Serena and in the inland Elqui Valley, where weather prospects are somewhat better. The northern part of the eclipse track crosses the Atacama Desert, and some of the world's great observatories—including the European Southern Observatory's La Silla Observatory—will experience totality. The shadow will then cross the Andes into Argentina's Cuyo region, where weather prospects are relatively good, and cross that country before the eclipse ends at sunset.
If you can't make it to this eclipse, in December 2020 another total solar eclipse will cross both Chile and Argentina a bit south of the path of the July 2 event, this time putting part of Patagonia in the Moon's shadow, at midsummer in the Southern Hemisphere.
Check out more details and some shots by the author of previous eclipses.
This composite series of images, taken by the author at the total solar eclipse of March 20, 2015 from Spitsbergen island in the Norwegian arctic, shows the progress of the eclipse from shortly after first contact (when the Moon first starts to "take a bite out of" the Sun) until totality.
A view of the entire path of totality for the July 2 solar eclipse, from Jay Anderson and Jennifer West's Eclipsophile meteorology site. The total eclipse starts in the South Pacific east of New Zealand, tracks between French Polynesia and Pitcairn Island, reaches its maximum duration of 4 minutes 52 seconds over open ocean, makes landfall on the Chilean coast in late afternoon, and ends at sunset southeast of Buenos Aires near the Atlantic coast.
This diagram, from the Eclipsophile eclipse meteorology site by Jay Anderson and Jennifer West, shows the average July cloud cover along the eclipse track in South America. When the Moon's shadow makes landfall north of La Serena, Chile, cloud cover averages just over 50 percent. It dips to 40 percent in the Elqui Valley, where many observers will be situated. Average cloud cover spikes to around 75 percent as the shadow crosses the Andes, while on the Argentine side of the Andes in the Cuyo region, with the mountains largely blocking Pacific weather patterns, cloud cover dips to 25 percent near Bella Vista, though at totality the setting Sun will stand at most a few degrees above the peaks there, so choose your location carefully. Cloud cover stays fairly low through central Argentina, but in eastern Argentina, which is affected by Atlantic weather systems, the average cloud cover increases, reaching nearly 70 percent when totality ends at sunset southeast of Buenos Aires.
A screenshot from the SkySafari 5 Pro app showing the eclipse circumstances from Oeno Island, with the planets labeled. The bright star to the eclipsed Sun's upper right is Sirius, while Orion stands upside-down (from a northern-hemisphere perspective) above the Sun. Eclipse-goers are only likely to notice the very brightest stars and planets.
Another image by the author from the March 20, 2015 total solar eclipse showing the so-called diamond ring, in which the last beam of direct sunlight, shining through a lunar valley, brightens a limb of the Moon in the moment before totality. A second diamond ring can be seen when totality ends.
This image, also taken by the author at the March 20, 2015 total solar eclipse, shows the solar corona, the Sun's superheated but tenuous atmosphere, surrounding the Moon's disk.
Eclipse circumstances for Bella Vista, Argentina. Although weather prospects are relatively good in western Argentina's Cuyo region, the Sun at totality will only be a few degrees above the Andes, and if you set up in a valley, say, you run the risk of the Sun setting before totality begins, so choose your location wisely.
The Sun, still partially eclipsed, sets beyond Lake Turkana in Kenya on November 3, 2013. Photograph by the author.
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