éclipses

An eclipse is a celestial event in which one astronomical object is temporarily obscured by another as it passes into its shadow or blocks its light. Eclipses occur when the Sun, the Moon, and the Earth align closely in a straight line, within the narrow confines of the Moon's orbital nodes.

Solar eclipses occur at new Moon, when the Moon moves between the Sun and the Earth. Depending on apparent sizes and alignment, eclipses are classified as total (the Sun is fully covered in the Moon's umbra, revealing the solar corona), partial (only part of the Sun is blocked), or annular (the Moon is near apogee and appears smaller than the Sun, leaving a bright ring). The path of totality is typically a narrow track on the Earth’s surface, moving as the Moon’s shadow traverses the planet. Total solar eclipses last only a few minutes at any given location.

Lunar eclipses occur at full Moon, when the Earth lies between the Sun and the Moon. They are categorized as total (the Moon crosses the Earth’s umbra), partial (only a portion enters the umbra), or penumbral (the Moon passes through the outer shadow and dims subtly). Lunar eclipses are visible from broad areas of the night side of the Earth and last several hours.

Observing notes: Looking directly at a solar eclipse without proper eye protection is dangerous. For lunar eclipses, no special equipment is required, though binoculars or telescopes improve the view. Eclipses have contributed to scientific understanding, including measurements of the solar corona and tests of gravitational theories, and they appear in cultural history as notable natural events. The timing and recurrence of eclipses are described by the Saros cycle, about 18 years, 11 days.