4.6 Canadian Telescopes of Historical Importance

Dominion Astrophysical Observatory in Victoria, British Columbia, Canada

Since becoming operational in 1918, the 1.8 metre Plaskett has accumulated nearly a century of upgrades that make it 10,000 times more sensitive than when it was first built. The 1.8-m Plaskett Telescope can perform optical imaging as well as spectroscopy.  The Observatory has been designated a national historic site because of its important role in establishing Canada’s international scientific reputation in astronomy. Over the decades, these telescopes have contributed significantly to our understanding of the rotation, size and mass of the Milky Way, and of the rarefied interstellar medium between the stars. Recent projects include orbital determination of comets and asteroids, spectroscopy of magnetic stars, and ongoing studies of distant quasars and galaxies. A group called Friends of the Observatory is working to restore the glory of this telescope and conducts tours and star parties in the summer (https://centreoftheuniverse.org/).

Dominion Astrophysical Observatory

David Dunlap Observatory in Richmond Hill, Ontario, Canada

This opened in 1935. The David Dunlap Observatory (DDO) is the largest telescope in Canada. A number of important studies have taken place here, including providing the first direct evidence that Cygnus X-1 was a black hole, pioneering measurements of the distance to globular clusters and the discovery that Polaris was stabilizing.  The DDO property was 76.5 hectares (189 acres) bordered by Hillsview Drive to the north, Bayview Avenue to the east, 16th Avenue to the south and the Canadian National Railway Bala Line to the west.  The property was the site of a 19th century farmstead owned by Alexander Marsh, comprised of a brick farmhouse, a lane from Yonge Street, agricultural fields with hedgerows and an orchard.

The University of Toronto constructed the Observatory on the site. It included a dome, housing a 74-inch (1.88m) reflector telescope, and an 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.

On September 29, 2009, Richmond Hill Council designated the DDO Property as a “property of cultural heritage value or interest” under Part IV, Section 29 of the Ontario Heritage Act.

David Dunlap Observatory

Attribution

“6.1 Telescopes” from Douglas College Astronomy 1105 by Douglas College Department of Physics and Astronomy, is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted. Adapted from Astronomy 2e.