If the Moon were in a perfectly circular orbit, a little closer to the Earth, and in the same orbital plane, there would be total solar eclipses every single month. However, the Moon's orbit is inclined (tilted) at more than 5 degrees to Earth's orbit around the Sun (see ecliptic) so its shadow at new moon usually misses Earth.
Earth's orbit is called the ecliptic
plane as the Moon's orbit must cross this plane in order for an eclipse (both
solar as well as lunar) to occur. In addition, the Moon's actual orbit is
elliptical, often taking it far enough away from Earth that its apparent size
is not large enough to block the Sun totally. The orbital planes cross each
year at a line of nodes resulting in at least two, and up to five, solar
eclipses occurring each year; no more than two of which can be total
eclipses.
However, total solar eclipses are rare at any particular
location because totality exists only along a narrow path on Earth's surface
traced by the Moon's shadow or umbra.
Special eye protection or indirect viewing techniques must
be used when viewing a solar eclipse to avoid eye damage.
When at a spot from which a 'total eclipse' is
visible, an observer can see a number of exciting effects. One such effect occasionally seen is Baily's
Beads where a sequence of spots of light appears along the edge of the Moon.
This is caused by the sun shining through the valleys of the Moon's mountainous
regions
The following table shows the upcoming total solar eclipses for the next few years:
| Date | Region Visible |
|---|---|
| 20 March 2015 | North Atlantic regions, Faroe Islands and the North Pole |
| 9 March 2016 | Indonesia |
| 21 August 2017 | Parts of the mid- and west USA |
| 2 July 2019 | central Argentina, Chile, the Tuamotus (French Polynesia), parts of the South Pacific Ocean |
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