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Espace pour la vie Invites You to Come and Observe the Transit of Mercury at the Planétarium Rio Tinto Alcan

Montréal, November 4, 2019 - 

On November 11, between 7:36 a.m. and 1:04 p.m., Quebec stargazers will have an opportunity to observe a rare astronomical event when Mercury passes directly between the Sun and the Earth! During the time that Mercury appears silhouetted against our daytime star, Montréal Space for Life invites you to join other astronomy buffs in observing this phenomenon. To fully appreciate the show without endangering your vision, it is crucial to use a telescope equipped with a filter specially designed for solar observation. If you miss this opportunity, you’re going to have to wait until 2049 for your next chance to view it!


The team at the Planétarium Rio Tinto Alcan and the volunteer members of the Société d’astronomie du Planétarium de Montréal will be welcoming observers outside in front of the planetarium between 7 a.m. and 1:15 p.m.

This activity is free. In case of poor weather conditions (totally overcast, low cloud ceiling, rain), observation may have to be temporarily suspended or even cancelled.
Note that no shows are scheduled that day at the Planétarium Rio Tinto Alcan, as it is currently closed Mondays.


  • Mercury is the closest planet to the Sun.
  • While it takes the Earth one year to orbit the Sun, Mercury completes its orbit in just 88 days.
  • On average, Mercury passes between the Sun and the Earth every 116 days. This phenomenon is called the inferior conjunction.
  • Usually, Mercury passes well above or well below the Sun, when viewed from the Earth, because its orbit is tilted 7° in relation to the Earth’s orbit. But on the rare occasions when the conjunction occurs during a window of a few days in early May or early November, the three bodies are so aligned that Mercury passes directly in front of the Sun, as seen from the Earth: this is called a transit.
  • Being a small planet, Mercury will take just under two minutes to cut across the edge of the solar disk, from 7:36:02 (7:36 a.m. plus 2 seconds) to 7:37:44,* Eastern Standard Time. *For places in Quebec far from Montréal, the exact times may differ by a few seconds from those indicated.
  • Maximum transit will take place at 10:20:13 a.m., with the Sun 25 degrees high in the south-southeast: Mercury will then be very close to the centre of the Sun’s disk.
  • The planet will exit the solar disk gradually between 1:02:41 p.m. and 1:04:22 p.m., Eastern Standard Time.


To observe, photograph or film the small round black silhouette of Mercury against the Sun, it is crucial to use an optical instrument that magnifies 50 to 100 times and is equipped with a filter specially designed for safe observation of the Sun.

Never look directly at the Sun. If you look at the Sun without an adequate filter, you could easily suffer permanent burns to your retina.

Transits of Mercury, but especially the much rarer transits of Venus, have left their mark on the history of astronomy. Careful observation of these phenomena served to establish the absolute scale of the distances between the planets in our solar system—and, from there, the distances to the stars. Today, the distance from the Earth to the other planets can be measured with a very high degree of accuracy (within a metre) thanks to radar returns. The transits of Mercury and Venus are now of interest mostly because they are rare. Next appointment to view is in 2049!

Check out Espace pour la vie’s website for more information on this phenomenon and advice for safe viewing:
Space for Life is made up of four attractions on the same site: the Biodôme, Insectarium, Jardin botanique and Planétarium Rio Tinto Alcan. These four prestigious municipal institutions form Canada’s largest natural science museum complex. Together, they are launching a daring, creative urban movement, encouraging all of us to rethink the connection between humankind and nature and cultivate a new way of living.

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Contact our team

Marie-Joëlle Filion
Communications Officer - Espace pour la vie
514 868-4840 / 514 443-6801

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