Solar eclipse 2027 › What is an eclipse?
What is a solar eclipse, and why does totality happen?
A solar eclipse occurs when the Moon passes between Earth and the Sun. Most alignments do not send the central lunar shadow onto the Earth's surface. When one does, the exact geometry decides whether observers see a total, annular or partial eclipse.
What happens during a solar eclipse
The Moon hides part or all of the solar disc and casts a shadow towards Earth. The dark central part of that shadow is the umbra. An observer reached by the umbra sees the Sun completely covered and is inside the path of totality.
A much wider area receives the penumbral shadow. From there, the Moon covers only part of the solar disc. This is a partial eclipse, even when the observer is very close to the edge of the total path.
Why there is not an eclipse at every new moon
The Moon's orbit is tilted relative to the plane of the Earth's orbit around the Sun. At most new moons, the lunar shadow passes above or below Earth.
An eclipse requires the new moon to occur near a point where the lunar orbit crosses that plane. Only then are the Sun, Moon and Earth aligned closely enough for the shadow to reach the surface.
Total, annular and partial are different events
- Total eclipse. The Moon covers the full solar disc. The corona becomes visible, and naked-eye viewing is permitted only during complete totality and only inside the path.
- Annular eclipse. The Moon appears too small to cover the Sun. A bright ring remains, so compliant solar filters are required throughout.
- Partial eclipse. The observer is outside the central path and part of the photosphere remains visible. Filters are required from beginning to end.
The safety rule follows the visible photosphere. If any part of the bright solar surface remains uncovered, direct viewing without a proper filter is unsafe.
Why the path of totality is narrow
The umbra reaches Earth as a narrow moving track. On 2 August 2027, the path of totality is about 258 km wide. Crossing its edge changes the event from total to partial.
Almería city is outside the path at 99.99% coverage. Roquetas de Mar, 16 km away, is inside and has 1 minute 37 seconds of totality. The difference is not a slightly better partial eclipse. It is a different physical circumstance.
Why the 2027 total eclipse lasts so long
The apparent sizes and relative motion of the Sun and Moon vary. For this eclipse, their geometry produces a long central total phase. Maximum totality is 6 minutes 23 seconds near Luxor in Egypt.
It is the longest total solar eclipse visible from land until 2114. Spain lies earlier on the path, where the duration is shorter: 4 minutes 48 seconds in Ceuta and 4 minutes 39 seconds in Tarifa.
The route on 2 August 2027
The total shadow crosses the Atlantic, the Strait of Gibraltar and southern Spain. It continues across Morocco, Algeria, Tunisia, Libya and Egypt, then the Red Sea, Saudi Arabia, Yemen, the Horn of Africa and the Indian Ocean.
Travellers must select an exact point on that route. See where to see totality and check the verified Spanish durations and time windows.
Solar and lunar eclipses are viewed differently
During a lunar eclipse, the observer looks at the Moon as it passes through the Earth's shadow. A solar eclipse involves looking towards the Sun, which requires strict protection whenever the photosphere is visible.
Read how solar retinopathy happens before observing. The eclipse-glasses guide explains how to recognise and inspect compliant direct viewers.
Last updated: 14 August 2026 · Editorial team