Why solar eclipses happen
A solar eclipse occurs when the Moon passes between Earth and the Sun and its shadow reaches Earth's surface. The alignment happens at new moon near one of the two points where the Moon's tilted orbit crosses the ecliptic.
The Moon's umbra produces totality in a narrow moving path. The surrounding penumbra covers a much larger region and produces a partial eclipse.
The four solar eclipse types
- Total: the Moon completely covers the Sun's photosphere for observers inside the umbra.
- Partial: only part of the photosphere is covered at the observer's location.
- Annular: the Moon appears too small to cover the Sun, leaving a bright ring.
- Hybrid: the central eclipse changes between total and annular along its path.
Local circumstances matter
The global label does not describe what every observer sees. A total eclipse may be partial from a nearby country, invisible because it occurs below the horizon, or already over before sunrise.
Useful local data includes first contact, maximum eclipse, last contact, obscuration, solar altitude, azimuth and, inside the central path, the duration of totality or annularity.
Observe without risking your eyes
Certified solar filters are required whenever any part of the photosphere remains visible. Totality is the only brief exception, and only for observers inside the path of a total eclipse.
Never use ordinary sunglasses or look through unfiltered optics. Binoculars, cameras and telescopes require filters mounted securely over the front aperture.
Scientific references
References used for eclipse dates, safety guidance and local calculations.