solar eclipse
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Annular eclipse photographed from Mazatlan, Mexico,
May 5, 2012, by Ray Stinson
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An eclipse in which Earth passes through
the shadow cast by the Moon. Solar eclipses
only happen when the Moon is new and when the Moon lies close to
the node of its orbit (i.e. when it's roughly
in the same plane as Earth's orbit). To see a total solar eclipse
the observer has to fall within in the Moon's umbra, the darkest part of
the lunar shadow, as it races across our planet. The path of totality
is never any wider than 270 km and, since it is swept out at some 3,200
km/hr, the length of totality at given location is never more than 7 minutes
31 seconds, and usually no longer than 3 or 4 minutes. A partial
eclipse is seen by observers in the Moon's penumbra, the partial
shadow, on either side of the path of totality. An annular eclipse
happens when the Moon is near apogee so that its apparent size is less than
that of the Sun and a ring, or annulus, of the Sun's
disk is still visible even when the Moon and Sun are seen directly in line.
The magnitude of a solar eclipse is the fraction of the
solar diameter obscured by the Moon at the greatest phase of an eclipse,
measured along the common diameter.
Related categories
• ECLIPSES
• SOLAR
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