Total solar eclipse of July 2, 2019 across the South Pacific, Chile, and Argentina
The first total solar eclipse anywhere in the world after the Great American Eclipse of August 21, 2017 comes to Chile and Argentina near sunset on July 2, 2019. The shadow of the Moon first touches Earth at the moment of sunrise at 37 South, 160 West in the South Pacific, east of New Zealand and south of Polynesia. Across the vast expanse of the Pacific, totality visits only one uninhabited island, Oeno, near Pitcairn Island.
While the eclipse of July 2, 2019 comes during the Austral winter, the sub-tropical latitude of about 30 degrees South will moderate temperatures. The Andean region at this latitude is famous for low humidity and clear skies at high altitudes. This bodes well for the prepared eclipse chaser and to stack your odds, consult the definitive web page on eclipse climatology for this eclipse is at eclipsophile.com/total-solar-eclipse-july-2-2019/
The focus for most eclipse chasers will be Chile and Argentina. Because landfall happens near the end of the path of totality, it will be near sunset for those viewing the total solar eclipse. The total eclipse will be approximately 12 degrees high when crossing the Andes in Chile and this will cause eclipse chasers to be careful to select a site not in a mountain shadow at that time. Another risk of a low sun altitude is that your line-of-sight to the eclipse could intercept more clouds. The maps on this page are custom designed to provide vital information to the prepared eclipse chaser, offering alternatives should the primary site be cloudy.
The total solar eclipse is significantly longer at sea for a maximum of 4 minutes and 33 seconds. Most of the path across the Pacific is far from any land, except near some southern islands of French Polynesia as well as Pitcairn Island, famous for a long-ago mutiny.
An interesting circumstance is that the total solar eclipse ends at sunset in the southern suburbs of Buenos Aires. For Argentinians in this area, an obstruction-free horizon, an elevated viewing site, and perfectly clear weather are needed for success. But should these circumstances align, perhaps from tops of buildings, it will be an unforgettable sight.
These maps feature very precise computations which take into account the Moon's precise shape (which can change the length of totality by a couple of seconds) as well as atmospheric refraction, important near the horizon.
The computation pipeline begins with Besselian Elements by retired NASA astrophysicist Fred Espenak, eclipsewise.com. Next, the computational engine of Solar Eclipse Maestro by Xavier Jubier is applied to compute eclipse circumstances for about 100 million points with latitude, longitude, and attributes such as contact times, duration, and sun altitude. You can find more maps and information at websites operated by Fred Espenak and Xavier Jubier.
These large point datasets are then processed with surface modeling tools in ArcGIS mapping technology by Esri. The maps are created in ArcGIS Pro and finished in Adobe Illustrator.
Most eclipse chasers are choosing land-based sites between La Serena, Chile and San Juan, Argentina. While the coastal area is frequently subject to marine fog and clouds, a drive to higher elevations will likely reach clear skies. After all, four major observatories (La Silla Observatory, Cerro Tololo Inter-American Observatory, Gemini South, and the Large Synoptic Survey Telescope under construction) are located in these mountains because of excellent clear-sky climatology. Some eclipse chasers are choosing land-based options in Argentina, mainly on the eastern side of the Andes. The advantage here is good mobility in two valleys and the chance for a photogenic composition framing the eclipse over mountains.
Totality is 2 minutes, 35 seconds where totality reaches Chile.
This map on the right shows the duration of total solar eclipse (corrected for the precise lunar profile), shadows cast by mountains at the time of eclipse near Vicuña, and a latitude-longitude graticule to assist in location with a GPS receiver.
Other options for eclipse chasing are by sea and air. Several cruises are scheduled in the vicinity of Polynesia and Pitcairn Island. It is very difficult to visit Oeno (the only South Pacific island within the umbra) because it is an uninhabited atoll with limited entry inlets.
Ships sailing from French Polynesia will proceed to the center of the path of totality for the longest eclipse duration of about three and a half minutes.
Further east in the Pacific, the point of longest eclipse has 4 minutes and 33 seconds of total eclipse.
A group of hardcore eclipse chasers are taking to the sky. Dr Glenn Schneider, one of the very most prolific eclipse chasers in history with 34 totals, has organized a flight to the South Pacific to intercept the eclipse. He has computed a precise flight path to extend the duration of totality to an extreme time length of between 8 minutes, 15 seconds and 9 minutes, depending on the high-altitude wind vectors.
While not as stable a photographic platform as land, the flight altitude is steady enough for scientific study and imagery and the duration of totality is double that from the sea! This remarkable flight is described here: http://nicmosis.as.arizona.edu:8000/ECLIPSE_WEB/TSE2019/TSE2019_EFLIGHTMAX.html
Most of South America experiences a partial eclipse between the late afternoon and sunset. The western section of South America will experience a partial eclipse with the Sun higher.
These are the maximum partial solar eclipse values for major cities:
San Jose, 5%
Panama City, 3%
Punto Arenas, 55%
Puerto Montt, 74%
Bahia Blanca, 90%
Buenos Aires, 99%.
Detail shadow maps
Most roads in the Andes in the path of totality lie in valley floors. With a low Sun altitude of 12 degrees during totality, the prepared eclipse chaser will have several alternate observation locales, depending on weather conditions that day. A novel feature of these maps is that they depict simulated shadows (computed in ArcGIS) at the time of totality. You can use a GPS receiver with this map to determine whether you are in a risky zone and the duration of totality you will experience.