SOLAR ECLIPSE

Despite a cloudy morning in Nairobi, Kenyans have been able to get a rare glimpse of the annular solar eclipse.

The eclipse which saw the sun completely ringed by the moon began at about 8.20am and could be seen for about 10 minutes.

The spectacle kept disappearing under the clouds but those who were patient caught glimpses on and off.

An annular eclipse occurs when the Moon passes directly in front of the Sun but does not completely obscure it, thus leaving a ring - an annulus - of sunlight flaring around the lunar disk.

This eight to 11 minute eclipse is "the longest annular eclipse of the 3rd Millennium," according to the National Aeronautics and Space Administration.

Only on December 23, 3043 will this record be beaten.

Apart from Friday\'s event, the only cover-up of the Sun this year will take place on July 11, when a total eclipse will cross the Pacific, visible notably from Easter Island, one of the world\'s remotest inhabited locations.
Total eclipses occur because of an unusual trick of celestial geometry.

The Sun is 400 times wider than the Moon, but it is also 400 times farther away. Because of the symmetry, the umbra, for those on the planetary surface, is exactly wide enough to cover the face of the Sun.

The orbits of the Earth and Moon are not completely circular, though. Tiny differences in distance explain why some eclipses are complete and others leave a thin ring of sunlight.

On December 21, 2010 - solstice day - there will be a total lunar eclipse, in which the full Moon will be covered completely by Earth's shadow for the first time in three years, according to Sky & Telescope.