Partial Solar Eclipse in London Ontario Monday August 21

The partial eclipse begins on the right side of the Sun’s disk just after lunch, at 13:07. Soon after this you will notice the black bite out of the Sun. Maximum eclipse occurs at 14:30, when 75% of the Sun will be blocked by the Moon’s disk. The Sun will be back to normal by 16:10 as the Moon moves off the left side of the Sun’s disk.

The RASC London Centre will support the event at the campus of Western University if you would like to have a fun and safe chance to view the partial solar eclipse.

This will not be a total solar eclipse here in London Ontario, but people who live south and west of Ontario see a thinner crescent Sun. You can still have a great experience observing the eclipse. Even a small crescent of the Sun’s disk is so bright that it will still be daylight. If you observe carefully you can tell the difference in the blue sky. Take your time and look through different telescopes to get the most enjoyment out of the experience.

What Actually Happens

An Eclipse Occurs because the Sun is about 400 times bigger than the Moon, but it is about 400 times farther away, so the Sun and the Moon appear to be the size in the sky. The Earth orbits the Sun and the Moon orbits the Earth. In this pattern of going around and round, sometimes the Moon crosses the line between the Earth and the Sun.

From our vantage point on the Earth, an eclipse occurs when the disk of the Sun is covered, whether partly or entirely. While the disk of the Sun is completely blocked, as seen from some points on the Earth, it is a total eclipse at those locations. This time, viewers across a strip of the U.S.A. get to see a total eclipse.

Here is a graphic of how the shadow will move across the Earth as the sun is eclipsed. In the middle of the circular shadow you can see a small black dot, which is the area of the total solar eclipse.

It’s the first time in 99 years that a total eclipse is visible only in the U.S.A. In this interactive app you can explore the circumstances of the eclipse in detail for any location in Canada or the United States. This map shows the complete path of the total eclipse across the United States, just in case you want to take a road trip.

For reference here is a map to give you an idea of what the eclipse will look like around North America.

How You Can Participate

RASC London Centre will support the event at the campus of Western University provided the sky is clear. Provided the sky is clear, a line of telescopes will be set up on the sidewalk on University College Hill. Visitors are welcome to come between 12:00 and 16:30 to view the eclipse and safe eclipse glasses will be provided free at the tent in front of University College. These will be collectors’ items forever! As well, as long as you take care of them, you will be able to view the sun any time you want to, as well as view any future eclipses.

A slide show will take place in the Cronyn Observatory where Scientists and RASC London Centre members will be on hand to answer questions and help you experience this marvel of nature. If it is overcast or even raining, then you won’t see the partial eclipse because it will be hidden by the clouds, but there will be a live TV feed in the Engineering Building that is next to the Cronyn Observatory on the University campus, in Room SEB 1200.

Other Events Happening

There is an event in Aylmer led by London Centre members on the sidewalk beside Balmoral Park in the town of Aylmer. There will be scopes, a pinhole box and safe eclipse viewers. The media is invited, to continue the tradition established at the very successful outreach
event 45 years ago
. We hope for fair weather!

Safe Viewing Methods for a Partial Eclipse

There are many ways to view a partial solar eclipse. Some are fun DIY projects, and others include use of commercial products and/or attachments to your telescope or binoculars. Below is a list of a few projects and ideas to view the eclipse. The RASC London Centre will support the event at the campus of Western University if you would like to have a fun and safe time view the partial solar eclipse.

  • Project the image of the Sun from a telescope on a screen
  • Cover your face with a proper eclipse viewer that reflects more than 99% of the light and only lets about 1% through to your eyes.  Be Sure To Check For Scratches!
  • Build a pinhole camera out of a shoebox or even something large enough to cover your whole head, then watch the small image of the Sun change shape inside the box
  • Use a colander or any object that has small holes in it to project small images of the Sun on the ground or any smooth surface, but don’t look through the object at the Sun.
  • Check out this link to make a Pinhole Camera.
  • Use a special solar filter to cover the front of your camera, binoculars or telescope. Be sure to buy a proper solar filter and check it carefully for flaws, scratches or cracks.
    • This is an advanced technique and should only be used by experienced science enthusiasts!

History of Solar Eclipses

Partial eclipses can be seen over a very wide area of the Earth’s surface, so they are quite common. There have been 56 partial eclipses visible in London since Confederation. The most recent partial eclipses that you might remember were: 2014-10-23 and 2013-11-03 and 2012-05-20 and 2002-06-10 and 2001-12-14. Other partial eclipses that baby boomers in London experienced occurred on: 1986-10-03 and 1984-05-30 and 1979-02-26 and 1970-03-07 and 1972-07-10 and 1963-07-20. The last time we had an eclipse as good as the one coming up this month was all the way back in 1994.

On 1994-05-10 London was almost exactly in the centre of the Moon’s shadow, but the Moon was a little farther from the Earth than average, and a bright ring of the Sun still brightened the sky at maximum eclipse. This type of event is called an annular eclipse. So check your diaries!

In a total eclipse, the Sun is completely blocked by the Moon’s disk. This kind of event is widely regarded as the most spectacular event in all of nature. However, they are quite rare at any particular point on the Earth. There hasn’t been a total eclipse over London, Ontario, since 1925-01-24, almost 100 years ago. In fact, we have had only three in the past thousand years. The other two were on 1451-06-28 and 1142-08-22. As for 1925-01-24, the sky in London was overcast that day, but there were a few breaks in the clouds, so some folks did see the event. Western’s campus was new, and it was cold that day! You can learn more about that day at An Historical Total Solar Eclipse in London, Ontario.

The next good opportunity to observe an eclipse here is fairly soon. On 2024-04-08 The Sun will be 97% covered. In fact, you will be able to enjoy a total solar eclipse that day just by driving down to St. Thomas or the Lake Erie shore, depending on weather. Travel east to Fort Erie, and you will actually be right on the centreline of totality.

For the rest of this century, partial solar eclipses will occur in London on 2021-06-10, on 2023-10-14, on 2045-08-12, on 2048-06-11, on 2057-07-01, on 2078-05-11, and 2079-05-01. On 2093-07-23 there will be another annular eclipse like the one in 1994. And then one more partial eclipse on 2099-09-14.

It is neat to think that children born around now may get to see all of these. The next time London actually gets to see a total solar eclipse without having to travel anywhere at all will be 2144-10-26. Lunar eclipses are something different, and we’ll provide information about those when the next one occurs.

For more information please contact the RASC at