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Sun Eclipses

IN SHORT - A solar eclipse is a major astronomical event. It occurs when the Moon occults the Sun to an observer on Earth. Albeit the Moon regularly orbits about the Earth, solar eclipses occur rarely, with a maximum of 5 eclipses for one given year. A solar eclipse may be total, annular or partial, with the solar disk being totally shadowed, left with a ring of light, or partially occulted only, respectively. 'Umbra', "penumbra' and 'antumbra' at the technical terms, designating the shadows

produced by the intervening Moon, which help describe the various types of a solar eclipse. The path of an eclipse is usually 10,000 mi long and 100 mi wide (16,000 km; 160 km) as the shadow is moving eastwards, generally
CAUTION! OBSERVING A SUN ECLIPSE IS DANGEROUS AND MAY CAUSE IRREVERSIBLE EYE DAMAGE, AND NEEDS YOU USE DEDICATED TECHNIQUES. see the insert below

CAUTION! OBSERVING A SUN ECLIPSE IS DANGEROUS AND MAY CAUSE IRREVERSIBLE EYE DAMAGE, ANNULAR AND PARTIAL ECLIPSES INCLUDED! Observing a Sun eclipse necessitates DEDICATED SAFE TECHNIQUES!

A solar eclipse occurs when the Moon, relatively to an observer, is screening the Sun. Although the Moon is orbiting Earth regularly, an eclipse does not occur at each time the Moon is in line, between the Sun and the Earth. The celestial mechanics makes the Moon be situated at the right place much less often

Depending on the position and the distance of the observer, any eclipse is total, annular, or partial. Is the observer, in line, sufficiently close to the Moon, the eclipse is total, that is that the observer is seeing the Moon larger than the Sun. The Sun is completely occulted. Is he, in line, further, the eclipse is annular. The observer sees the Moon smaller than the Sun. A ring of Sun is seen all around the Moon's disk. Is the observer, at any distance, shifted relative to the axis of the eclipse, he does see a partial eclipse only. A part of the solar disk is occulted only

Theoretically, these situations are described as the observer being in any of three kinds of Moon's shadow, the "umbra", the "antumbra", or the "penumbra", three Latin words meaning "shadow", "anti-shadow", and "near shadow". The situations, on the other hand, may be taken at the reverse, by considering the observer in abstract no more, but the position of the Moon instead, relative to the observer, located on the Earth this time. When the observer is where the "umbra" reaches Earth, there is a total eclipse. When he is where it's the "antumbra" which hits Earth, there is an annular eclipse. In both cases, if the observer is where the "penumbra" is, he sees a partial eclipse only.
total and annular eclipse
Should neither the "umbra" or the "antumbra" touch Earth in any place, but the "penumbra" only, there is a partial eclipse, independently of any total or annular eclipse. The combined effects, at last, of the Moon's distance and of the curvature of the Earth may yield what is called a "hybrid", or "annular-total" eclipse. At the beginning and the end of the eclipse's journey, it's the "antumbra" which reaches Earth only, as along the eclipse, it's the "umbra" which does. The eclipse begins and ends as annular as in-between it's total. Like for a total and an annular eclipse, such hybrid eclipses are accompanied by a partial eclipse. The variation of the distance of the Moon to the Earth is due to that the Moon's orbit is not a circle but an ellipse, hence Moon's apparent diameter is seen varying

Technically, total, annular, and hybrid eclipses are "central eclipses" as the central axis of the eclipse hits the Earth, as partial eclipses only are "non-central eclipses" as the axis hits nowhere. As far as statistics are concerned, the balance is as follow as far as the different types of eclipses are concerned: total eclipses account for 26.6 percent of the total of the eclipses, annular eclipses for 32.9 percent, hybrid for 5.2 percent. Partial eclipses only account for 35.3 percent

Due to the respective motions of the Moon and the Earth, an eclipse, of whatever sort, is moving. When it's about a total or an annular eclipse -and a hybrid eclipse, the "umbra" or the "antumbra" follow what's called a "path". It's the eclipse's path, or path of the shadow, or the "central line". The eclipse's path is usually about 10,000 miles long and 100 miles wide. Eclipse is most of the time moving eastwards. Eclipse's duration is rarely above several minutes. When the eclipse is total, observers are granted by a great show, with the corona's streamers surrounding the occulted Sun as both the beginning and the end of the totality are heralded by the Baily's beads and the "diamond ring". The darkening during an annular eclipse is function of the percentage of the ring of Sun remaining surrounding the Moon's disk. The "diamond ring" phenomenon is seen during an annular eclipse too. As far as partial eclipses are concerned, the farther the line of centrality, the lesser the part of the solar disk seen occulted by the Moon and the nearer, the opposite

click here for a video (Windows Movie Player, .wmv format, 1.6 Mb) of the illustration of a total solar eclipse!

There may be between 2 and 5 solar eclipses each year but there can not be more than 7 eclipses (solar, and lunar) in one given year: 4 solar eclipses and 3 lunar eclipses; or 5 solar eclipses and 2 lunar