Umbral Path and Visibility

Due to the large value of gamma (=0.918) at this eclipse, the Moon's umbral shadow remains close to Earth's limb throughout the event. Thus, the Sun never climbs higher than 23º along the entire track. The path of the umbral shadow begins at sunrise in easternmost Kazakhstan at 00:41 UT (Figures 3 and 4). However, it requires an additional four minutes for the northern edge of the shadow to contact Earth. At this time (00:45 UT), the path is 318 kilometers wide and the southeast edge of the umbra alreadyreaches deep into central Mongolia while the northwest edge has yet to make planetfall. An observer on the center line will then witness a total eclipse lasting 2 minutes 11 seconds with the Sun 6º above the eastern horizon. One minute later (00:46 UT), the umbra makes its first interior contact and the entire shadow now falls completely on Earth. Neglecting Earth's curvature, the shadow is an ellipse of high eccentricity (e=0.991 or 916 x 126 kilometers) as it rushes eastward with a ground velocity of 1.9 km/s.

Mongolia's capital city Ulaanbaatar lies just south of the path and experiences a tantalizing partial eclipse of magnitude 0.996 at 00:48 UT. Only 0.2% of the Sun's photosphere will then be exposed and it may be possible to see the corona and the diamond ring effect if skies are clear. By 00:50 UT, the shadow's velocity and ellipticity have decreased to 1.6 km/s and e=0.977 (610 x 130 kilometers), respectively. From the center line, the Sun's altitude is 12º and the duration of totality is 2 minutes 24 seconds. The industrial city of Darchan lies within the path ~30 kilometers south of the center line where the total phase is diminished by only one second from maximum duration. North of the path, the Russian hydroelectric city of Irkutsk also witnesses a deep partial eclipse of magnitude 0.988 at 00:54 UT.

Traveling eastward, the shadow quickly crosses the Mongolian-Russian border as it passes south of Lake Baikal, the world's largest fresh water lake. At 00:55 UT, the path width is 361 kilometers, the center line duration is 2 minutes 33 seconds and the Sun's altitude is 16º. Ulan-Ude lies just outside the northern limit and witnesses a partial phase of magnitude 0.998; only 0.1% of the Sun will then be visible. As the shadow's track curves northward, it engulfs the largest city in its path. Cita (pop. = 366,000) experiences mid eclipse at 01:00 UT and enjoys 2 minutes 15 seconds of totality. About 100 kilometers to the south, the center line duration lasts 2 minutes 39 seconds at a solar elevation of 18º.

Although the umbra first touched Earth a mere nine minutes earlier, it has already traveled 2,000 kilometers. At 01:08 UT, Russia's city of Mogocha witnesses a 2 minute 32 second total eclipse with the Sun at 20º. The shadow's course takes it increasingly northward where its southern half briefly enters the northern provinces of China (01:10 UT). The instant of greatest eclipse occurs shortly thereafter at 01:23:48.5 UT. Totality then reaches its maximum duration of 2 minutes 50 seconds, the Sun's altitude is 23°, the path width is 356 kilometers and the umbra's velocity is 0.836 km/s. From this point on, the path rapidly turns north and crosses some of the most desolate regions of northern Siberia. Finally, the umbra reaches the coast of the East Siberian Sea at 01:52 UT. The umbral duration (2m33s), path width (314 km), and Sun's altitude (16º), are now decreasing while the shadow's ground velocity is increasing (1.3 km/s).

Continuing north across the East Siberian Sea and the Arctic Ocean, the Moon's umbra leaves Earth's surface near the North Pole at 2:06 UT. During the eighty minutes of central eclipse, the broad umbral shadow travels approximately 6800 kilometers, and encompasses 0.4% of Earth's surface.

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