On Monday, April 8th, 2024, the total solar eclipse will cross North America, passing over Mexico, the United States and Canada. Dubbed the “Great North American Eclipse”, this will be the first total solar eclipse to be visible in provinces of Canada since February 26, 1979 and the only one where totality will be visible in the 21st century. If you miss your chance to view this total solar eclipse, the next one will take place in the Contiguous United States on August 23, 2044. Here are some tips, tricks and stories about how to watch the Total Solar Eclipse.
What is a solar eclipse and how is totality defined?
A solar eclipse happens when the Moon in its orbit passes directly between the Earth and the Sun, with the Moon blocking the Sun’s light. The Sun is about 400 times larger than our Moon, but it also happens to be about 400 times farther away from Earth, which means they look about the same size in the sky.
Sometimes the moon only blocks part of the Sun’s circle: that would be a partial eclipse. But, more rarely, the Moon blocks all the Sun’s light and that is the rare total solar eclipse. During a total eclipse, the whole of the Sun is blocked by the Moon. This means that none of its light reaches us, and so we're standing in the Moon's shadow. There are only certain points on Earth that are completely in the Moon’s shadow and this April, Southern Ontario will be one of those places. This period when the Sun is completely blocked is called totality. It will only last a few minutes, but is the most exciting and dramatic moment of an eclipse -- imagine a very short night, but in the middle of the day!
We will not see a total solar eclipse in Southern Ontario for a long, long time. It’s a very rare event because eclipses don't happen very often and even when they do only a small part of the Earth’s surface experiences a total eclipse. The next one in Canada is in Alberta but not until 2044.
Why is this solar eclipse important and when will it next be seen? Why so long?
Worldwide, total eclipses are quite common, usually occurring once every few years. However, from any particular location, they are very rare, and so it's really exciting to have one taking place so close to Waterloo! The eclipse in April will be the first in Southern Ontario since 1925, and the last one here until 2144.This means there won’t be another in Ontario in the whole 21st century!
The Moon goes around the Earth once a month, so you might expect us to have a total eclipse every month, but total eclipses are much more rare. This is because of the tilt of the Moon's orbit: the Moon's orbit around the Earth is offset from the Earth's orbit around the Sun by an angle of about five degrees. This means that the Moon is usually either above or below the Earth's orbit, and so it usually just passes by the Sun in the sky. The only time when both of these orbits happen to line up is during a total eclipse!
How are Department members celebrating this?
The Waterloo Centre for Astrophysics is running several eclipse-related events that are open for anyone to attend! On March 27th, Dr. Roan Haggar will be speaking about the eclipse at Kitchener Public Library, and the WCA is also taking part in an event on April 4th celebrating perspectives on the eclipse from different faculties at the University.
A lot of Department members in Waterloo are travelling south for the eclipse. Waterloo will unfortunately only witness a 99% partial eclipse, meaning 1% of the Sun will still be visible. However, that 1% makes a lot of difference! Others like Dr. Haggar will be driving just south of Waterloo, but as the eclipse will be visible all over North America, some department members are planning to go eclipse-chasing to find the clearest sky possible!
What are some tips (viewing safety and astrophotography) to viewing the solar eclipse and joining local events?
The most important thing is to try to get hold of a pair of solar eclipse glasses. Even during a total eclipse, looking at the Sun is dangerous and can cause permanent damage to your eyes. In order to watch the eclipse safely, you must wear eclipse glasses that satisfy the official ISO 12312-2:2015 safety standard. Normal sunglasses are not sufficient -- eclipse glasses are more than 1000 times darker than these! You can watch a quick video about solar eclipse glasses and how to safely view a solar eclipse with Professor Emeritus Ralph Chou from the School of Optometry.
The only time you do not need to wear your glasses when looking at the Sun is during "totality", when the Sun is fully blocked by the Moon. During this time it is safe to remove your glasses, but you must put them back on before any part of the Sun becomes visible again.
You can also view the eclipse with a pinhole camera (there are lots of instructions on how to build these online), or with a solar filter than can be attached to a camera or telescope. Again, it is extremely important to use these properly and safely, otherwise you risk causing immediate damage to your eyes.
If you can't go to the local events, how can you enjoy the solar eclipse at home? Watch online / livestreams? Recommendations?
If you can't travel, a 99% eclipse will still be exciting, especially viewed through a pair of eclipse glasses. If you're lucky enough to live in the path of totality, it will be an amazing event regardless of whether you go to a viewing event!
Alternatively, there will be livestreams of the eclipse available online from all across Canada and the US. NASA will be running a live stream throughout the entire event that is free for anyone to watch.
We look forward to having you share your eclipse experiences with us! Send photos or a message to our Alumni Engagement Office!
Eclipse Perspectives Event
The registration for the Eclipse Perspectives event is now open! Click here to find out more!
