Your guide to enjoying eclipses and protecting your eyes

This article is courtesy of the Canadian Space Agency. To see it in its entirety, with videos and images, visit
An eclipse is a wonder to behold. Although eclipses occur more often than you might think, there aren't many opportunities to admire them. There are four to seven eclipses per year, but only those people along the path of an eclipse are able to see it.

When will the next solar eclipse be visible in Canada?

On Monday, August 21, 2017, a partial solar eclipse will be visible in Canada.

Important: Looking directly at the Sun, without appropriate protection, can lead to serious problems such as partial or complete loss of eyesight.

During a solar eclipse, it is imperative to wear special glasses with filters designed for eclipse watching (ISO 12312-2 international standard) to prevent eye damage. Regular sunglasses will not protect your eyes sufficiently.

When watching a partial solar eclipse, proper eye protection is required at all times.

What is an eclipse?

An eclipse occurs when the light of a body outside Earth's atmosphere (Sun, Moon, planets, etc.) is temporarily blocked by another body. Eclipses don't just happen on Earth: they also take place on other planets, like Jupiter and Neptune.

What is a solar eclipse?

A solar eclipse occurs when the Moon comes between the Earth and the Sun, casting a shadow on Earth.

From the locations along the Moon's umbra trajectory, it appears as if the Sun has gone dark. Depending on the distance between the Sun and the Moon and their positions, it is possible to see three kinds of solar eclipses:
  • Total eclipse: the Moon completely covers the Sun
  • Annular eclipse: the Moon is closer to the Sun; hence the Moon appears smaller than the Sun. A ring of light from the Sun is always visible
  • Partial eclipse: the Sun and the Moon are not perfectly aligned, so only a part of the Sun is hidden by the Moon
  • Total solar eclipse of August 21, 2017
  • On August 21, 2017, a total solar eclipse will cross the entire United States (from west to east). Fourteen US states will be lucky enough to witness it in its totality, and the other US states and Canada will be treated to a partial eclipse.
  • The path of totality is a narrow corridor approximately 100 to 115 km wide where the Sun will appear to be completely covered by the Moon for a short period of time (between 2 and 3 minutes). This is the most spectacular part of the eclipse, as those who are lucky enough to be in this corridor will be able to see the Sun's corona, the chromosphere, prominences and streamers. Proper eye protection is essential before and after totality.
  • For those outside the path of totality, the Sun will appear to be partially covered by the Moon (partial eclipse), and proper eye protection is required at all times.

Will this solar eclipse be visible in Canada?

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