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David Dunlap Observatory, Richmond Hill, 1935

Date1935
FormatPicture
Notes
Observatory (1935), (David Dunlap Observatory), Richmond Hill.
Inscribed, lower middle: "F W Jopling David Dunlop Observatory"

The Richmond Hill David Dunlap Observatory (RHDDO) houses 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 RHDDO 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.
When the observatory in downtown Toronto could no longer function due to light pollution, the University of Toronto identified the Marsh farmstead as being suitable for a new astronomical facility. As a result, Jessie Donalda Dunlap purchased the property and donated it to the University as a memorial to her husband, David Alexander Dunlap, who was an avid astronomer.

The University 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.

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.  
https://www.richmondhill.ca/en/learn-more/ddo-history.aspx 
GeographyBuilding Monument ParkDavid Dunlap Observatory
GeographyCity, town, townshipRichmond Hill
GeographyProvince stateOntario
GeographyCountryCanada
DimensionsImage size: 11.1 cm x 18.8 cm (4 3/8 in. x 7 3/8 in.)
Language
Usage Rights Public Domain (Learn More)
Object Number977-45-2-Cab