The Dark Elf
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http://news.bbc.co.uk/1/hi/sci/tech/4299074.stm
A dark shadow is about to be thrown over much of Europe, Africa, Asia and the Middle East in an annular eclipse.
Monday will see the Moon sweep across the face of the Sun for a dazzling display of celestial mechanics.
An annular eclipse is less spectacular than a total solar eclipse because the sky never goes completely black; but it should, nonetheless, be quite a show.
In the right places, skywatchers should see a blazing ring of fire surround the Moon's disc.
Once again, though, astronomers are urging those without the proper viewing equipment not to look directly at the Sun with the naked eye; blindness could result.
In and out
In the UK, only a partial eclipse will be visible; the Moon will be seen to take a large chunk out of the Sun.
Depending on where one is standing, between 44% (Aberdeen) and 64% (Plymouth) of the Sun will be covered, according to the Society for Popular Astronomy.
In London, this partial eclipse starts at 08:48BST and ends at 11:18BST.
Not every eclipse can be total. The Moon's orbit around the Earth is not perfectly round; the satellite's distance from the planet varies from about 356,000 to 407,000km (221,000 to 253,000 miles).
This difference makes the Moon's apparent size in our sky fluctuate by about 13%.
If the Moon happens to eclipse the Sun on the near side of its orbit, it totally blocks out the star (a total eclipse).
But if the Moon eclipses the Sun on the far side of its orbit, the satellite will not completely obscure the star's disc - and a ring or annulus of sunlight is seen.
The effect is to throw an "antumbra" or "negative shadow" on the Earth's surface as the Moon moves across the face of the Sun. It is the track of this antumbra that is referred to as the "path of annularity".
And although the daylight will significantly dim for those in this path, a substantial portion of sunlight will still be visible and potentially highly dangerous to anyone tempted to squint at the eclipse.
Unless you have access to a telescope or binoculars equipped with proper solar filters, or approved eclipse glasses, the advice is to use a pin-hole camera technique to project the eclipsing Moon and Sun on to a piece of paper.
A good option will be to watch the event on one of several websites geared up to stream it.
The path of annularity across the Earth's surface begins out in the North Atlantic at 08:41GMT. Its snake-like route then takes it across the Iberian Peninsula, passing Madrid at 08:56 GMT; crossing the western Mediterranean and moving on to the African continent, and arriving at Algiers a 09:05GMT.
From there, the path follows a south-eastern route, through southern Tunisia and central Libya.
After briefly skirting northern Chad, the antumbra sweeps across central Sudan where the period of greatest eclipse will be experienced at 10:31GMT.
The 'beads'
The annular duration here will last four minutes and 31 seconds, according to the US space agency's "Mr Eclipse", Fred Espenak, who has become an oracle for eclipse calculations.
The path then heads along the southern Sudanese-Ethiopian border before entering Kenya and Somalia. It leaves land at 11:30GMT and only a ship in the Indian Ocean could experience the end of the eclipse at 12:22GMT.
Those lucky enough to be in the path of annularity and with clear skies should look for the "beads" or "gems" that skirt the fiery ring.
These are caused by sunlight streaming through valleys and past mountains on the Moon's surface.
This is the fourth annular eclipse of the 21st century. The next total solar eclipse is on 29 March, 2006. It will traverse equatorial West Africa, the Sahara, the western Mediterranean, Turkey and Russia.
Picked a good day to do it, eh bliink
A dark shadow is about to be thrown over much of Europe, Africa, Asia and the Middle East in an annular eclipse.
Monday will see the Moon sweep across the face of the Sun for a dazzling display of celestial mechanics.
An annular eclipse is less spectacular than a total solar eclipse because the sky never goes completely black; but it should, nonetheless, be quite a show.
In the right places, skywatchers should see a blazing ring of fire surround the Moon's disc.
Once again, though, astronomers are urging those without the proper viewing equipment not to look directly at the Sun with the naked eye; blindness could result.
In and out
In the UK, only a partial eclipse will be visible; the Moon will be seen to take a large chunk out of the Sun.
Depending on where one is standing, between 44% (Aberdeen) and 64% (Plymouth) of the Sun will be covered, according to the Society for Popular Astronomy.
In London, this partial eclipse starts at 08:48BST and ends at 11:18BST.
Not every eclipse can be total. The Moon's orbit around the Earth is not perfectly round; the satellite's distance from the planet varies from about 356,000 to 407,000km (221,000 to 253,000 miles).
This difference makes the Moon's apparent size in our sky fluctuate by about 13%.
If the Moon happens to eclipse the Sun on the near side of its orbit, it totally blocks out the star (a total eclipse).
But if the Moon eclipses the Sun on the far side of its orbit, the satellite will not completely obscure the star's disc - and a ring or annulus of sunlight is seen.
The effect is to throw an "antumbra" or "negative shadow" on the Earth's surface as the Moon moves across the face of the Sun. It is the track of this antumbra that is referred to as the "path of annularity".
And although the daylight will significantly dim for those in this path, a substantial portion of sunlight will still be visible and potentially highly dangerous to anyone tempted to squint at the eclipse.
Unless you have access to a telescope or binoculars equipped with proper solar filters, or approved eclipse glasses, the advice is to use a pin-hole camera technique to project the eclipsing Moon and Sun on to a piece of paper.
A good option will be to watch the event on one of several websites geared up to stream it.
The path of annularity across the Earth's surface begins out in the North Atlantic at 08:41GMT. Its snake-like route then takes it across the Iberian Peninsula, passing Madrid at 08:56 GMT; crossing the western Mediterranean and moving on to the African continent, and arriving at Algiers a 09:05GMT.
From there, the path follows a south-eastern route, through southern Tunisia and central Libya.
After briefly skirting northern Chad, the antumbra sweeps across central Sudan where the period of greatest eclipse will be experienced at 10:31GMT.
The 'beads'
The annular duration here will last four minutes and 31 seconds, according to the US space agency's "Mr Eclipse", Fred Espenak, who has become an oracle for eclipse calculations.
The path then heads along the southern Sudanese-Ethiopian border before entering Kenya and Somalia. It leaves land at 11:30GMT and only a ship in the Indian Ocean could experience the end of the eclipse at 12:22GMT.
Those lucky enough to be in the path of annularity and with clear skies should look for the "beads" or "gems" that skirt the fiery ring.
These are caused by sunlight streaming through valleys and past mountains on the Moon's surface.
This is the fourth annular eclipse of the 21st century. The next total solar eclipse is on 29 March, 2006. It will traverse equatorial West Africa, the Sahara, the western Mediterranean, Turkey and Russia.
Picked a good day to do it, eh bliink
