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Partial Solar Eclipse today – 10/06/21



Article submitted by Richard Bullock in Wilmslow, Cheshire


On Thursday 10th June 2021, Wilmslow, along with most of Northern and Western Europe together with eastern Canada, most of Russia and northern China, has a view of an interesting partial solar eclipse taking place in the high Arctic.

A solar eclipse occurs when the Moon passes in between the Earth and the Sun, blocking out the light from the Sun for up to a few minutes. An eclipse doesn’t happen every time the Moon is between the Earth and the Sun as the Moon’s orbit is tilted with respect to that of the Earth. Most of the time, therefore, the Moon will pass either above or below the Sun. We only see an eclipse when the alignment is perfect.

This time, however, the Moon is currently too far away from Earth to completely block the view of Sun anywhere on the planet. Instead, viewers on the perfect alignment path between Earth, Moon and Sun will see an Annular Solar Eclipse, where a thin circular ring of the Sun can be seen around the Moon’s shadow – the so-called “Ring of Fire”. The perfect alignment only makes landfall in the far north of Canada, Greenland and the far east of Siberia, but interestingly also passes directly over the geographic North Pole.

The eclipse begins with what is called “First Contact”, where the first “bite” is taken out of the right-hand side of the Sun, which will take place at 10:08 am. Maximum eclipse, where about a quarter of the Sun’s surface area at the top will be blocked by the Moon, takes place around 11:14. The photograph shows roughly what this should look like from Wilmslow. The eclipse ends at 12:25 where the last part of the Moon leaves the Sun on the top-left. These timings are accurate for Wilmslow. If you are further away then the timings might vary slightly. It’s unlikely to get noticeably darker during this degree of partial eclipse, but eclipses do sometimes modify the behaviour of animals and birds for a time.

Those intending to watch the eclipse will need to make sure they are doing so safely. Looking directly at the Sun can seriously damage your eyesight or cause permanent blindness unless you have the correct eye protection, and you should especially never look directly at the Sun through binoculars or a telescope. You will need to use a proper solar filter or specially made solar eclipse glasses for looking at the Sun directly. Sunglasses are not enough, and even normal shade welding glasses won’t give you the right level of protection. Welding glasses need to be at least shade 14 for solar viewing, but these should not be combined with a telescope or binoculars.

A safer method is to project an image of the Sun onto a piece of paper, for instance using a simple pinhole camera, rather than observing the Sun directly.

There is one final thing to watch out for. Near the time of maximum partial eclipse, whilst most people are looking upwards, there is something interesting to see by looking downwards too. The small gaps between leaves and branches of trees act a bit like a pinhole camera and in each gap will be projected a mini image of the partially eclipsed Sun onto the ground. Consequently, you may be able to see hundreds of little eclipsed Suns in the shadows on the ground. If you haven’t got any suitable trees nearby, you can make some gaps using your hands, or use something like a colander to simulate this effect.

Let’s hope the weather stays cooperative. If on the day it is cloudy, then there are likely to be several live-streams available where you can watch the eclipse online.



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