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Eclipse Description

eclipsi logo min.JPG


On Wednesday, March 29 of this year, a total eclipse will be visible from within a narrow corridor, which traverses half the Earth. The path of the Moon's umbral shadow begins in Brazil and extends across the Atlantic, northern Africa, and central Asia, where it ends at sunset in western Mongolia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the northern two thirds of Africa, Europe, and central Asia.


The central eclipse track begins in eastern Brazil, where the Moon's umbral shadow first touches down on Earth at 08:36 UT. Along the sunrise terminator, the duration is 1 minute 53 seconds from the center of the 129-kilometre wide path. Traveling over 9 km/s, the umbra quickly leaves Brazil and races across the Atlantic Ocean (with no landfall) for the next half hour. After crossing the equator, the Moon's shadow enters the Gulf of Guinea and encounters the coast of Ghana at 09:08 UT. The Sun stands 44° above the eastern horizon during the 3 minute 24 second total phase. The path width has expanded to 184 kilometres while the shadow's ground speed has decreased to 0.958 km/s. Located about 50 kilometres south of the central line, the 1.7 million inhabitants of Ghana's capital city Accra can expect a total eclipse lasting 2 minute 58 seconds (09:11 UT).

Moving inland the umbra enters Togo at 09:14 UT. Unfortunately, the capital city Lome lies just outside the southern limit so its inhabitants will only witness a grazing partial eclipse. Two minutes later, the leading edge of the umbra reaches Benin whose capital Porto-Novo experiences a deep partial eclipse of magnitude 0.985. Continuing northeast, the shadow's axis enters Nigeria at 09:21 UT. At this time, the central duration has increased to 3 minutes 40 seconds, the Sun's altitude is 52°, the path of totality is 188 kilometres wide and the velocity is 0.818 km/s. Since Lagos is situated about 120 kilometres outside the umbra's southern limit, its population of over eight million will witness a partial eclipse of magnitude 0.968.

The umbra's axis takes about sixteen minutes to cross western Nigeria before entering Niger at 09:37 UT. The central duration is 3 minutes 54 seconds as the umbra's velocity continues to decrease (0.734 km/s). During the next hour, the shadow traverses some of the most remote and desolate deserts on the planet. When the umbra reaches northern Niger (10:05 UT), it briefly enters extreme northwestern Chad before crossing into southern Libya.


The instant of greatest eclipse[1] occurs at 10:11:18 UT when the axis of the Moon's shadow passes closest to the center of Earth (gamma[2] = +0.384). Totality reaches its maximum duration of 4 minutes 7 seconds, the Sun's altitude is 67°, the path width is 184 kilometres and the umbra's velocity is 0.697 km/s. Continuing on a northeastern course, the umbra crosses central Libya and reaches the Mediterranean coast at 10:40 UT. Northwestern Egypt also lies within the umbral path where the central duration is 3 minutes 58 seconds.


Passing directly between Crete and Cyprus, the track reaches the southern coast of Turkey at 10:54 UT. With a population of nearly 3/4 million people, Antalya lies 50 kilometres northwest of the central line. The coastal city's inhabitants are positioned for a total eclipse lasting 3 minutes 11 seconds while observers on the central line receive an additional 35 seconds of totality. Konya is 25 kilometres from path center and experiences a 3 minute 36 second total phase beginning at 10:58 UT. Crossing mountainous regions of central Turkey, the Moon's shadow intersects the path of the 1999 Aug 11 total eclipse. A quarter million people in Sivas have the opportunity of witnessing a second total eclipse from their homes in less than seven years.

At 11:10 UT, the shadow axis reaches the Black Sea along the northern coast of Turkey. The central duration is 3 minutes 30 seconds, the Sun's altitude is 47°, the path width is 165 kilometres and the umbra's velocity is 0.996 km/s. Six minutes later, the umbra encounters the western shore of Georgia. Moving inland, the track crosses the Caucasus Mountains, which form the highest mountain chain of Europe. Georgia's capital, Tbilisi, is outside the path and experiences a magnitude 0.949 partial eclipse at 11:19 UT. As the shadow proceeds into Russia, it engulfs the northern end of the Caspian Sea and crosses into Kazakhstan. At 11:30 UT, the late afternoon Sun's altitude is 32°, the central line duration is 2 minutes 57 seconds and the umbral velocity is 1.508 km/s and increasing.

In the remaining seventeen minutes, the shadow rapidly accelerates across central Asia while the duration dwindles. It traverses northern Kazakhstan and briefly re-enters Russia before lifting off Earth's surface at sunset along Mongolia's northern border at 11:48 UT. Over the course of 3 hours and 12 minutes, the Moon's umbra travels along a path approximately 14,500 kilometres long and covers 0.41% of Earth's surface area.

[1] The instant of greatest eclipse occurs when the distance between the Moon's shadow axis and Earth's geocentre reaches a minimum.

[2] Minimum distance of the Moon's shadow axis from Earth's center in units of equatorial Earth radii.

(Visibility maps from F. Espenak, NASA/GSFC)

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