Richmond Hill David Dunlap Observatory – Site of the Largest Telescope in Canada


The Town of Richmond Hill is reopening the David Dunlap Observatory for public programming.


The David Dunlap Observatory (DDO) is the largest telescope in Canada. From 1935 to 2007, the Observatory was at the forefront of Canadian astronomical research. It is rich in history with many cultural and natural heritage features, including the meadows and wetlands, the Elms Lea farmhouse, the Administration Building and the Observatory.


  • The Observatory opened on May 31, 1935, a gift to the University of Toronto by Jessie Donalda Dunlap as a memorial to her husband, David Alexander Dunlap, a prominent lawyer and co-founder of Hollinger Gold Mines.
  • It included the Dome, housing a 74-inch (1.88m) reflector telescope, and the Administration Building, with three smaller telescope domes.
  • When construction was complete in 1935, the main telescope was the second largest in the world and the largest in Canada.
  • From 1935 to 2007, the Observatory was at the forefront of Canadian astronomical research.
  • Achievements at the site included advances in radio astronomy and the first direct evidence that Cygnus X-1 was a black hole.
  • From 2009 to 2016, York Region Astronomy Association held classes and other Starnight programs at the Observatory.

The Town of Richmond Hill is in the process of developing David Dunlap Observatory Park into the preeminent public parks in the Greater Toronto Area, where visitors come to see Canada’s historic observatory, celebrate the stars and enjoy acres of natural parkland.


The programming will include:

  • Summer camps for 9 to 12-year-olds are taking place at the Richmond Hill DDO in July and
  • Astronomy-themed speaker nights and stargazing for amateur astronomers begin in June.
  • Lecture nights and astronomy events will also be available for families.
  • Group bookings for astronomy programs will soon be open to school groups and special interest

You may like: Fun Things to Do this Summer in Richmond Hill

How to get to the Observatory:

123A Hillsview Drive, Richmond Hill

Ample Parking Available



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