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 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 74-inch (1.9 m) telescope (left) and Administration Building (right) at the David Dunlap Observatory
Concept sketch of David Dunlap Observatory
David Alexander Dunlap, c. 1920
Construction of the observatory's dome in Newcastle upon Tyne, after which it was dismantled and shipped to Richmond Hill
The Toronto Magnetic and Meteorological Observatory is a historical observatory located on the grounds of the University of Toronto, in Toronto, Ontario, Canada. The original building was constructed in 1840 as part of a worldwide research project run by Edward Sabine to determine the cause of fluctuations in magnetic declination. Measurements from the Toronto site demonstrated that sunspots were responsible for this effect on Earth's magnetic field. When this project concluded in 1853, the observatory was greatly expanded by the Canadian government and served as the country's primary meteorological station and official timekeeper for over fifty years. The observatory is considered the birthplace of Canadian astronomy.
The Toronto Magnetic and Meteorological Observatory on the grounds of the University of Toronto
The original observatory: the main building is on the right, with the dome visible, and the roof of the smaller buried building is just visible over the fence. Painted by William Armstrong in 1852.
The newer observatory before it was moved, looking towards the southwest. This image is the same orientation as the one below, viewed from the left of the tower.
The observatory in 2009, looking east-southeast. Offices on the ground floor have been rotated; the entrance was formerly to the right of the tower.