Skywatchers in for a treat
2005-09-30 17:45
Paris - Skywatchers are in for a rare treat on Monday when an annular eclipse will darken the Sun in a swathe across Europe, Africa, Asia and the Middle East.
In an annular eclipse, the Moon moves between the Sun and Earth but, because of a tiny difference in distance due to celestial mechanics, does not completely cover the solar face as in a total eclipse.
Instead the Moon appears as a shaded disk, with a dazzling, beaded corona around its rim.
The corridor in which this dramatic event can be seen is a narrow one, snaking from the North Atlantic, where it starts at 08:41 GMT, across the Iberian peninsula and then to northern and eastern Africa before petering out in the Indian Ocean at 12:22 GMT.
Countries to be affected
Countries that lie on this path comprise Spain, notably in Madrid (best viewing is at 08:56 GMT), as well Algeria, Tunisia, Libya, northern Chad, central Sudan, southwestern Ethiopia, Kenya and Somalia.
The maximum duration of "annularity" will be four minutes, 31 seconds, when the Sun is high overhead in central Sudan, according to the US publication Sky & Telescope.
Cities that lie north and south of the corridor will get a partial eclipse, in which the errant Moon will appear to take a bite out of the Sun.
They include Berlin, London, Moscow, Reyjkavik, Rome, Jerusalem, Tehran and Istanbul, says NASA expert Fred Espenak. Even locations as distant as Johannesburg and New Delhi will, weather permitting, get a tiny partial eclipse.
Fourth of the century
It is the fourth annular eclipse of the 21st century.
Total eclipses happen about once every 18 months, although these usually fall over the sea or uninhabited areas.
The next total eclipse, on March 29 2006, will traverse equatorial West Africa, the Sahara, Western Mediterranean, Turkey and Russia.
Eclipses hold a special place in myth and superstition as the forebringers of great events such as droughts, floods and storms, famine, defeat at war and the birth and death of kings.
In ancient China, the belief was that an eclipse was caused when the gods dispatched a dragon to eat the Sun.
The monster then had to be chased away with dances, incantations, the clashing of cymbals and gongs, and the unleashing of arrows and fireworks.
Even the word "eclipse" comes from a Greek word, "ekleipsis", which means to fail or be abandoned.
Anyone who watches an eclipse should only use special filters, never the naked eye, sunglasses or a makeshift object such as a coloured bottle.
Even at its darkest, an eclipsed Sun still emits light in the non-visible, ultraviolet range of the energy spectrum, and without protection this can badly damage the retina.
Further information on (http://sunearth.gsfc.nasa.gov). Includes addresses of websites that are running live webcasts of the eclipse.
- SAPA