David Dunlap Observatory

NOTE: PROGRAMS AT THE DAVID DUNLAP OBSERVATORY ARE CURRENTLY SUSPENDED WHILE THE NEW OWNERS, THE TOWN OF RICHMOND HILL, DECIDES ON USE OF THE FACILITY.

The David Dunlap Observatory is home to the largest optical telescope on Canadian soil with a primary mirror measuring more than 1.88 metres (74 inches) in diameter. Constructed in the 1930s, the Observatory is located in the heart of Richmond Hill, Ontario. The building is 18.6 metres (61 feet) in diameter and the rotating dome weighs 73 metric tons. The telescope itself weighs 21 metric tons (without its primary mirror).

Until August 2016, RASC Toronto Centre volunteers managed the Observatory and adjacent Administration building, providing public education and outreach programs to thousands of people each year.

As home to the largest volunteer-managed telescope in the world regularly open for public star gazing, the David Dunlap Observatory provides a model for reuse and repurposing of retired observatories.

Our stewardship has allowed the Great Telescope to remain operational and introduced thousands of visitors to astronomy and the history of space science.

The DDO is located at 123 Hillsview Drive in Richmond HIll. Hillsview can be reached from Bayview Avenue, north of 16th Ave.
Address: 
David Dunlap Observatory 123 Hillsview Drive Richmond Hill, ON, L4C 1T3
Phone Number: 
905-883-0174
Latitude: 
43' 51' 46" N
Longitude: 
79' 25' 21" W
Parking: 
There is plenty of parking, though our public events have been known to fill up. Gates usually open an hour or two before an event, and remain closed when the facility is not in use.