Partial Solar Eclipse Today!

Tonight, right around sunset, there will be a partial eclipse of the sun, visible from most of North America.  As the sun sets, skywatchers will get to see the moon gradually cover about half of the sun, before it disappears below the horizon.

A map of the viewing area shows that the best spot to see it will be all the way up in the Canadian arctic.

Solar eclipse visibility map – October 23rd, 2014 Credit: Science@NASA

If you don’t live in the Arctic circle, you can certainly see the eclipse in the South-West near the horizon as it sets.  The moon will start to cover the sun around 5:45 EDT, and the event will last until sunset at 6:20pm (in Toronto).

 

What is a Solar Eclipse?

A solar eclipse occurs when the Moon is perfectly aligned between the Earth and the Sun.  The Moon casts a shadow on the Earth, which is seen by Earthbound observers as a ‘darkening’ of the sun as the Moon covers it.

The sun and Moon are the same size in the sky, about the size of a Nickel (a Canadian 5 cent piece) held at arm’s length.  This is because the Moon is 400x closer to the Earth then the Sun, while also having a diameter 400x smaller than the Sun.  So when the Moon covers the Sun during a total eclipse, the Corona of the Sun, which translates to ‘crown,’ becomes visible as a halo of light shooting out in all directions.

Orientation of the Sun, Moon, and Earth during a solar Eclipse.
Totality, the Moon completely covers the Sun. Credit: NASA

It can be difficult to see the ‘Totality’ as in the above image, because the Moon’s shadow is so small.  Unless you are in the precise path of the Moon’s shadow on Earth, you won’t see the Total Eclipse.  Instead you would see part of the Sun covered by the Moon,  a ‘crescent’ Sun.

Total Solar Eclipse of the Sun – August 21st, 2017

The closest thing North American observers will get is the August 21st, 2017 Total Solar Eclipse.  Better book your hotel soon, tons of travellers will be making the trip to catch this one.

So if you miss the partial eclipse this evening, you can hold out for 2017, though you should take every opportunity, it could be cloudy in 2017!

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