A total solar eclipse crossed the Arctic, northeastern Greenland, western Iceland, the North Atlantic, northern Spain and a small area of Portugal on Aug. 12, according to NASA. A partial eclipse was visible across parts of the northern United States from Alaska to North Carolina, most of Canada, much of Europe and northwestern Africa.
It was Spain’s first total solar eclipse since 1905.
Duration and timing
Totality lasted under two minutes for most observers within the path. Near the centre line, over Greenland, northern Russia and the open North Atlantic, it remained under two and a half minutes.
The shadow crossed different regions at markedly different local times. Totality occurred at midday in a remote area of northern Russia, in the late afternoon or early evening over Greenland and Iceland, and in the late evening shortly before sunset in Spain and the northwestern tip of Portugal.
Obscuration outside the path
NASA’s figures for maximum obscuration in cities outside the path of totality: Madrid and Barcelona both reached 99%, Algiers 96%, Lisbon 95%, Dublin 94%, Paris and Milan 92%, London 91%, and Berlin and Vienna 85%.
At 99% obscuration the remaining sliver of photosphere is approximately ten thousand times brighter than the corona. The sky does not darken appreciably, the corona is not visible, and eye protection remains necessary throughout. The distinction between locations inside and outside the path is absolute rather than incremental.
Coverage across the United States was limited with about 9% in New York and 37% in Fairbanks.
Low sun angle and eclipse photography
The low altitude of the sun during totality in Spain permitted compositions combining the eclipsed sun with terrestrial foreground in a single frame, which is not possible when totality occurs at high sun angles.
NASA’s Astronomy Picture of the Day for Aug. 13 featured an image by Ruiyu Zhang taken from Zaragoza, showing the eclipse above the Cathedral-Basilica of Our Lady of the Pillar and reflected in the Ebro River.
Scientific observation
Totality allows ground-based observation of the solar corona without the photosphere’s glare. NASA notes that eclipse observations contribute to research on why the corona reaches temperatures millions of degrees higher than the solar surface below it.
NASA also identifies eclipses as an accessible target for citizen science, given that the path is narrow and totality brief, so distributed observers can collect data no single research team can gather simultaneously. Useful contributions include temperature and cloud-cover logging, coronal imaging for aggregation into composite datasets, and records of animal and insect behaviour during totality.
NASA’s Earth Observatory published Landsat 9 imagery of Iceland’s Snæfellsnes peninsula acquired July 25, showing the ice-capped Snæfellsjökull volcano. The surrounding national park was among the limited landfall points along the path and drew eclipse viewers.
Viewing safety
NASA’s guidance for future eclipses:
-Direct viewing without protection is safe only during totality itself.
-Solar viewing glasses and handheld solar viewers should comply with the ISO 12312-2 standard. Sunglasses are not adequate at any darkness.
-Cameras, telescopes and binoculars must not be used while wearing eclipse glasses. Concentrated sunlight will burn through the filter. Optics require a dedicated solar filter mounted at the front.
-Indirect methods, including pinhole projection, allow safe observation of partial phases.
Subsequent eclipses visible from Spain
A total solar eclipse will be visible from Spain on Aug. 2, 2027, followed by an annular eclipse on Jan. 26, 2028. After 2028, the next total solar eclipse visible from Spain occurs in 2053.
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