[Total Solar Eclipse: 2017]
The 2015 Eclipse:
The Total Solar Eclipse of 20 March 2015.
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 bottom to top on the map). At the point of Greatest Eclipse, totality is at local midday. The duration of totality at greatest eclipse is 2 minutes 47 seconds. This occured in the North Atlantic Ocean. On either side of that point, the duration of totality is less. To the West (left and lower) of the point of greatest eclipse, the eclipse was total before local noon; East (right and upper) of this point, 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. 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 late March this point is on the equator. The parts in red on either end of the umbra are the regions where the eclipse occurs with the Sun on the horizon.
The Moon's shadow (umbra) touched down on the Earth at 09:09 (UT) in the North Atlantic Ocean south of Greenland. At this point the width of the shadow was 406km and the duration of totality was 2m 05s at local sunrise.
The shadow then moved Eastwards across the sea travelling at approximately 1km per second before turning to the North East and passing between the British Isles and Iceland without touching either.
The shadow made the first of two landfalls at 09:40 when it covered the Faroe Islands. The small village-like capital of Torshavn experienced 2m 00s of totality. The West and North parts of the islands fared a little better with just over 2m 20s. The width of the umbra over the Faroes was 443km with the islands 80km from the centre line where totality was 2m 40s.
The umbra quickly left the Faroe Islands and continued turning Northwards over the Arctic Ocean. The umbra reached the point of Greatest Eclipse at 09:45 where totality was 2m 47s with the shadow 462km wide and the eclipse occurring at local Noon.
The shadow then continued in a more Northerly direction.
At 10:09 the umbra made its second and final landfall on the Norwegian islands of Svalbard. The largest settlement of Longyearbyen enjoyed 2m 25s of totality. The umbra was 414km wide as it passed over these islands which straddled the centre line.
The umbra left the Earth at 10:21 close to the North Pole where the Sun is perpetually on the horizon at this time of year. The duration of totality was now 2m 06s and the path width was 408km.
The umbra took 1 hours 12 minutes to traverse its entire path, covering less than half a percent of the Earth's surface.
The Path of Totality (the Moon's umbra) is the shaded area moving across the North Atlantic Ocean from bottom left to upper right.
The umbra passes between Iceland and the British Isles, passing over the Faroe Islands.
In 1954 the Moon's umbra passed over most of the Faroe Islands giving them two total eclipses in 61 years.
The Faroe Islands are located just within the Path of Totality about 120km from the centre line.
The duration of totality at Torshavn (the small capital of the islands) was 2 minutes 00 seconds (increasing as you move North West).
Our eclipse site was the Smyril Line ferry marked with a yellow X.
|Date||20 March 2015|
|Location||Torshavn - Faroe Islands, Denmark|
|Latitude||62° 00' 24" N|
|Longitude||6° 45' 54" W|
|Altitude||approx. 60 m|
|Distance from Centre Line||about 150 km|
|1st Contact (UT + 0)||08:38|
|Duration of Totality||2m 00s|
|Path Width||440 km|
|Major Axis||471 km|
|Minor Axis||146 km|
|Direction of Shadow Approach||210°|
|Umbral Velocity||0.897 km/s|
|Position Angle: 2nd Contact||102°|
|Position Angle: 3rd Contact||216°|
|Saros Details||120 (61 / 71)|
The Location, Latitude, Longitude and Altitude (in metres) are for the observation site at Torshavn, the capital of the Faroe Islands. The figures were measured on the GPS system on the Smyril Line ferry.
The Distance from Centre Line was estimated from Google Interactive maps provided by Fred Espenak.
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 + 0 (GMT).
The Duration of the eclipse at the observation site was 2 minutes 00 seconds.
The Path Width is the width of the path of totality. The umbra itself was very 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 471km long and 146km wide and produced a path width of 440km.
The Direction of the Shadow indicates that the umbra approached the observation site from the South West. The Umbral Velocity is the speed of the Moon's shadow (just under 900 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. These figures determine the position of any diamond rings 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 0.9454. This means that the shadow passes close to the most Northerly part of the Earth. This, combined with the fact that in March, neither pole is tilted well towards the Sun, produces an eclipse mainly in the high Northern 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 1.044 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 120. It is the 61st eclipse out of a total of 71 in the series.
The series began on 27 May 933 with a small partial eclipse in the Antarctic regions. This was followed by 6 partial eclispes of increasing magnitude as the Moon's shadow moved closer to the Earth's centre with each successive eclipse. On 11 August 1059, 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 1m 6m 10s duration occurred. The series consisted of 25 more annular eclipses. Their duration increased to 6m 24s before decreasing as the Moon approached the Earth. On 8 May 1510, the eclipses became hybrid, that is annular along some of the path and total along other parts.
The first completely total eclipse of the series occurred on 20 June 1582 (the 37th eclipse of the series, duration 1m 59s). Saros 120 has 26 total eclipses and after the first, the duration slowly increased as the Moon continued to approach the Earth. The longest duration was reached on the 60th eclipse (9 March 1997) which was 2m 50s long. During totality, some observers saw Comet Hale-Bopp.
The current (61st) eclipse of this saros is the penultimate total eclipse of the series.
The final total eclipse of Saros 120 (the 62nd of the series) will occur on 30 March 2033 (duration 2m 37s).
The series ends with nine partial eclipses, the final one being a small partial (4%) in the Arctic on 7 July 2195. The entire series will last for 1262 years.
At any one time dozens of Saros series are in progress. Other eclipses will belong to different series.