[Total Solar Eclipse: 2017]
The 2008 Eclipse:
The Total Solar Eclipse of 1 August 2008.
The narrow blue region is the Path of Totality (also known as the Umbra).
The Moon's umbra (shadow) travels from west to east (left to right and top to bottom on the map). At the point of Greatest Eclipse, totality is at local midday. The duration of totality at greatest eclipse is 2 minutes 27 seconds. This occured in northern Siberia (Russia). On either side of that point, the duration of totality is less. To the West of greatest eclipse the eclipse was total before local noon; East of it, totality was seen after local noon. The umbra is generally widest around the time of greatest eclipse as the Earth is bulging out towards the Moon in that region. This brings the Earth's surface closer to the Moon.
The area on either side of the path of totality (in pale blue) is called the Penumbra and provided a partial eclipse, the magnitude decreasing with distance from the path of totality. The UK experienced a partial eclipse of approximeately 12%. Beyond the partial region no eclipse is visible.
The Sub-solar Point is the location where the Sun is overhead at the time of greatest eclipse; in August this point is North of the equator. The parts in red on either end of the umbra are the regions where the eclipse occurs during sunrise (top) or sunset (right).
The path of totality begins in northern Canada (at sunrise) and passes over northern Greenland. Passing through the Arctic Ocean close to the North Pole, the path passes through large areas of Siberia (Russia), where the greatest eclipse occurs. The path then crosses the region where Russia, Kazakhstan, Mongolia and China all meet.
The path leaves the Earth in central China (at sunset).
The umbra takes 2 hours 00 minutes to traverse its entire path of 10,200km, covering 0.4% of the Earth's surface.
The path of totality is the pair of black lines moving across Siberian Russia from top left to bottom right. The red line is the centre line.
It takes about 40 minutes for the umbra to cross this region.
The red lines crossing the path are the positions of the umbra at ten minute intervals (all in Universal Time which is essentially GMT). For each position, the accompanying boxes contain the time of mid-eclipse, the duration of totality, and the altitude of the Sun.
The Path of Totality passing through Siberian Russia.
Our base was in Novosibirsk but our eclipse site was on the south side of the inland sea (the Ob Sea) to the south.
The eclipse site was at Staribirsk, a small beach to the North West of the city of Berdsk (marked with a yellow X).
|Date||1 August 2008|
|Location||Staribirsk - Ob Sea near Birdsk (Siberia)|
|Latitude||54° 47' 33" N|
|Longitude||83° 02' 22" E|
|Distance from Centre Line||less than 10 km|
|1st Contact (UT + 7)||16:42|
|Duration of Totality||2m 19s|
|Path Width||248 km|
|Major Axis||255 km|
|Minor Axis||129 km|
|Direction of Shadow Approach||approx. 330°|
|Umbral Velocity||0.976 km/s|
|Position Angle: 2nd Contact||118°|
|Position Angle: 3rd Contact||298°|
|Saros Details||126 (47 / 72)|
The Location, Latitude, Longitude and Altitude (in metres) are for the observation site at Staribirsk, a beach on the Ob Sea at Berdsk in Siberian Russia, south of the city of Novosibirsk. The figures were measured on a Garmin GPS 12 Personal Navigator.
The Distance from Centre Line was provided by Fred Espenak and confirmed from a map.
First Contact is the beginning of the eclipse when the first "bite" appears on the Sun's disk; it is the beginning of the partial phase. Second Contact is the beginning of totality. Third Contact is the end of totality. Fourth Contact is the end of the partial eclipse. The times are in local time which, for this eclipse, is UT + 7 (GMT plus six hours plus an extra hour for summer time).
The Duration of the eclipse at the observation site was 2 minute 19 seconds.
The Path Width is the width of the path of totality. The umbra itself is elliptical in shape. The Major Axis is the longest axis of the umbra; the Minor Axis is the shorter axis. The umbra at the observation site was 255km long and 129km wide and produced a path width of 248km. The path width was wide enough to make the eclipse reasonably dark. The elliptical shape of the umbra was noticeable during totality.
The Direction of the Shadow indicates that the umbra approached the observation site from the North West. The Umbral Velocity is the speed of the Moon's shadow (976 metres per second) at the observation site. This and the umbral width determine the duration of the total eclipse.
The Sun's Altitude is measured from the horizon; the Azimuth is the direction of the Sun measured clockwise from North. The figures are for mid-eclipse. The Position Angles indicate the exact position of the Sun's disk where the Moon covers and uncovers the Sun at the beginning and end of totality.
Gamma determines how the Moon's shadow, if extended, would pass through the Earth. A Gamma of zero implies that the shadow would pass through the exact centre of the Earth. A Gamma of greater than 1 misses the Earth and no total eclipse would occur. A positive Gamma passes North of the Earth's centre; a negative Gamma passes South of the Earth's centre. The value of Gamma for this eclipse is 0.8307. This means that the shadow passes well North of the Earth's centre, about a 83% of the way to the edge of the Earth. This, combined with the fact that in early August, the Northern Hemisphere is tilted towards the Sun, produces an eclipse mainly in the Northern polar regions.
The Diameter Ratio determines how much bigger the Moon's apparent radius is than the Sun's. In this case, the Moon's radius is 1.0384 that of the Sun's. A total eclipse can only occur if this figure is greater than 1. The Moon would then appear larger than the Sun and could cover it completely. If this figure was less than one a total eclipse could not occur because the Moon would appear smaller than the Sun.
The Obscuration determines how much larger the Moon's apparent area is than the Sun's.
The Saros is a collection of eclipses belonging to a series. Each member of the series is followed by a similar eclipse approximately 18 years, 11 days and 8 hours later. This eclipse is a member of Saros number 126. It is the 47th eclipse out of a total of 72 in the series.
The series began on 10 March 1179 with a small partial eclipse in the Antarctic regions. This was followed by 7 partial eclispes of increasing magnitude as the Moon's shadow moved closer to the Earth's centre with each successive eclipse. On 4 June 1323, the Moon's shadow finally made contact with the Earth but the Moon was too far to cover the Sun completely and an annular eclipse of 5m 59s duration occurred. The series consisted of 27 more annular eclipses of decreasing duration as the Moon approached the Earth. On 14 April 1828, the eclipses became hybrid, that is annular along some of the path and total along other parts. There were three of these.
The first completely total eclipse of the series occurred on 17 May 1882 (the 40th eclipse, duration 1m 50s). Each subsequent eclipse has been of longer duration, reaching a maximum duration of 2m 36s on 10 July 1972 (the 45th eclipse of the Saros, one I saw as a 20% partial eclipse from London). The final total eclipse of Saros 126 occurs on 23 August 2044. After a series of 24 partial eclipses in the northern polar regions, the Saros will end on 3 May 2459.
Saros 126 will have lasted for 1280 years.
At any one time dozens of Saros series are in progress. Other eclipses will belong to different series.