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March 23, 2006
WAUKESHA, WI – On March 29, the normally sunny African sky will darken as the Moon covers the Sun. A total solar eclipse occurs when our satellite passes between Earth and our star. Although the Moon is 400 times smaller than the Sun, the Sun lies 400 times farther from Earth. So, when this celestial lineup is dead-on – as it will be March 29 – the two bodies possess the same angular size (about 1/2º), and a total solar eclipse occurs.
Before reaching Africa, however, this total eclipse begins over Brazil at sunrise. The eclipse path then crosses the Atlantic Ocean, reaching landfall again on the African coast. More than 1.5 million people in Ghana’s capital, Accra, will experience totality for nearly 3 minutes. Maximum eclipse occurs over the Chad-Libya border, where observers will experience 4 minutes and 7 seconds of totality.
The eclipse path then crosses Egypt and the Mediterranean Sea, and enters Turkey. The eclipse ends at sunset over northern Mongolia. The path of totality spans only 114 miles (184 kilometers), but observers over a much wider area of northern Africa, Europe, and central Asia will see a partial solar eclipse.
Darkness during the day
Watching an eclipse is a spectacular sight – an initial dark bite grows and swallows the Sun’s yellow globe. In a total eclipse, all that’s left is the Sun’s glowing, outer atmosphere called the corona. In the minutes before totality, the landscape gains a golden hue, shadows become sharper, and the temperature falls. Slivers of sunlight shine through valleys on the Moon’s edge and create what are called Baily’s beads. The beads gradually disappear until a solitary spot remains – an effect called the diamond ring. Darkness ensues, and then the process repeats, in reverse.
Use extreme caution when viewing the Sun. At no point during any eclipse is it safe to look directly at the Sun without a proper filter. Use an approved coated-glass or optical Mylar solar filter or a #14 welder’s glass.
The next total solar eclipse occurs August 1, 2008. It follows a path over northern Canada, Greenland, Siberia, Mongolia, and China.
Astronomy takes you there
Astronomy magazine and Astronomical Tours are leading two groups to view the March 29 eclipse. Editor David J. Eicher, Senior Editor Michael E. Bakich, and tour participants will watch the eclipse from a ship in the Mediterranean Sea, off the Greek coast. Senior Editor Richard Talcott and a group will observe it from Cappadocia, Turkey.
Watch for reports on Astronomy.com and for full coverage in Astronomy magazine’s July issue. The next Astronomy trip is a “Winter Solstice Tour” in Peru and Bolivia, June 22-July 2, 2006. For more information, visit www.astronomy.com/tours.