David Dunlap Observatory

The David Dunlap Observatory (DDO) is an astronomical observatory site in Richmond Hill, Ontario, Canada. Established in 1935, it was owned and operated by the University of Toronto until 2008. It was then acquired by the city of Richmond Hill, which provides a combination of heritage preservation, unique recreation opportunities and a celebration of the astronomical history of the site. Its primary instrument is a 74-inch (1.88 m) reflector telescope, at one time the second-largest telescope in the world, and still the largest in Canada. Several other telescopes are also located at the site, which formerly also included a small radio telescope. The telescope was driven by the vision of astronomer Clarence Chant, shared by businessman David Alexander Dunlap – whose family provided financial support after Dunlap's death in 1924. The scientific legacy of the David Dunlap Observatory continues in the Dunlap Institute for Astronomy & Astrophysics, a research institute at the University of Toronto established in 2008. The DDO is the site of a number of important scientific studies, including pioneering measurements of the distance to globular clusters, providing the first direct evidence that Cygnus X-1 was a black hole, and the discovery that Polaris was stabilizing and appeared to be "falling out" of the Cepheid variable category. Located on a hill, yet still relatively close to

Observatory data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).