Partial Lunar Eclipse TONIGHT [Archives:2006/979/Local News]

August 7 2006

SANA'A, Sept.7 ) ( ) Experienced eclipse observers will be able to watch the second half of a partial eclipse of the Moon after sunset on 7 September, people in Yemen will be able to witness the whole event starting from 16:42 GMT, 18:42 local time in Yemen.

Lunar eclipses take place when the full Moon is exactly in line with the Earth and Sun and it moves into the Earth's shadow. They can be seen wherever the Moon is above the horizon and so from a given spot on the Earth's surface are much more common than solar eclipses, although they are still unusual events.

North Americans will be completely shut out of this event, as it will be happening during the daytime when the Moon is below the horizon. This eclipse will be primarily visible from western Australia, central Asia, and the eastern half of Africa. Europe will see the Moon rise while in eclipse, while eastern Australia and New Zealand will see the Moon set (for them it's the morning of September 8) while still in eclipse.

The dark umbral phase lasts just over 90 minutes and even at its maximum, the eclipse magnitude – that percentage of the Moon's diameter that will be within the Earth's umbral shadow – is only 19 percent. That dark shadow will create little more than a 'bite' out of the Moon's upper rim.

The first event, at 16:42 GMT is the Moon entering the penumbra, the faint outer extremity of the Earth's shadow. But this shadow is so light that the Moon doesn't begin to change appearance until the Moon's diameter has penetrated it by at least 70 percent (17:40 GMT/ 19:40 local time). Around that time, look for a very slight shading or smudginess on the upper left portion of the Moon. As the minutes pass, the penumbra becomes more obvious.

The next event to watch for is at 18:05 GMT (20:05 local time), as the Moon enters the umbra, the dark inner part of the Earth's shadow. This is the beginning of the partial eclipse. The umbra is much darker than the penumbra and fairly sharp-edged. The partial eclipse only lasts 1 hour 33 minutes. Maximum eclipse will come at 18:51 GMT (20:51 local time). After maximum eclipse, the Moon will soon exit the umbra at 19:38 GMT (21:38 local time). About 25 minutes later, the faint penumbral shading should gradually fade away.

The next lunar eclipse will be a total eclipse on March 3 of next year and will be visible from Europe, Africa and western Asia. That event will also be visible from the eastern half of North America; for many localities the eclipse will already be underway as the Moon rises.