eelvarjutus

Eelvarjutus is the early phase of an eclipse, a term used in astronomy to describe the period before the main phase when the obscuration begins but has not yet reached its maximum. The word is formed from eel-, meaning before, and varjutus, meaning eclipse, reflecting its place in the sequence of eclipse events.

In solar eclipses, eelvarjutus refers to the initial stage when the Moon first contacts the Sun and the visible solar disk begins to disappear. This phase precedes the period of greater obscuration and, for total solar eclipses, the moment of totality. The duration of eelvarjutus varies with the geometry of the Sun, Moon, and Earth and is typically short compared with the overall eclipse.

In lunar eclipses, eelvarjutus denotes the onset of shading as Earth's shadow starts to cover the Moon. This marks the earliest detectable change in the Moon’s appearance and leads up to the deeper, partial, or total eclipse phases.

Observational notes emphasize safety for solar viewing: during eelvarjutus, as the Sun becomes progressively more obscured, it may still be dangerous to look at directly without appropriate eye protection. The phase is primarily of interest for timing, geometry, and historical records, providing data on the relative positions and motions of the Earth, Moon, and Sun.

See also: varjutus, päikesevarjutus, kuuvarjutus, maksimaalne varjutus.