Partial solar eclipse
2015 Sep 13
Dominic Ford – originally published on In-The-Sky.org
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There will be a total solar eclipse, best seen from Antarctica (Sun 71% covered), Bouvet Island (Sun 60% covered), French Southern Territories (Sun 40% covered), Heard Island and McDonald Islands (Sun 32% covered) and South Africa (Sun 32% covered). From United Kingdom no eclipse will be visible. To see information about the times when the eclipse will be visible elsewhere in the world, select a different location. The globe to the right shows the path of the Moon’s shadow across the Earth during the eclipse. The shaded region within the red contour shows all of the places where the Moon covers any part of the Sun’s disk. Within this, white contours show where the Moon covers 20%, 40%, 60% and 80% of the Sun. The central white dot shows places where the Moon covers more than 98% of the Sun. The map below shows a projection of the Moon’s shadow onto a map of the world, with the same contours marked. |
Visibility of the eclipse
The map below shows contours of the maximum extent of the eclipse across the world.
The geometry of solar eclipses
Solar eclipses occur when the Sun, Moon and Earth are aligned in an almost exactly straight line, with the Moon in the middle, such that the Moon passes in front of the Sun.
Solar eclipses are only ever visible from certain parts of the world because the Moon is so close to the Earth – 390 times closer than the Sun – that its position in the sky differs by up to two degrees (four times its diameter) from one side of the Earth to the other. So, while it may cover the Sun as seen from one location, it may not even touch it as seen from the other side of the world.
Solar eclipses take place when the Earth moves through the Moon’s shadow. The dark gray cone behind the Moon indicates the region of space in which the Moon appears to completely cover the Sun’s disk (the Moon’s umbra). The light gray area around it shows where the Moon appears to partially cover the Sun’s disk (the Moon’s penumbra).
On this occasion, however, the alignment will not be very exact, and while the Moon will brush the side of the Sun – a partial solar eclipse – nowhere on Earth will see it entirely cover the Sun’s disk.
Further details
This eclipse is a member of Saros series 125. The position of the Sun at the moment of greatest eclipse will be:
| Object | Right Ascension | Declination | Constellation | Angular Size |
| Sun (centre) | 11h23m | +03°58′ | Leo | 31’47” |
The coordinates above are given in J2000.0.
The details of this observing event were provided courtesy of In-The-Sky.org
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