Description of Historic Place

David Dunlap Observatory National Historic Site of Canada consists of four buildings on a 40-hectare campus. It includes: the Observatory Building, the Administration Building, Elms Lea (Director’s House), and the Radio Shack, as well as an antenna field. The Observatory Building is situated on a hill which rises 30 metres above the surrounding countryside. This steel frame structure consists of a massive dome atop a two-storey cylindrical base, and houses a 74 inch reflecting telescope. South of the Observatory Building is the Administration Building, a two-storey sandstone-clad Beaux-Arts building topped by three telescope domes. Behind this building, to the east, is the Radio Shack, a small single-storey wood-frame building. Located in the southwest of the property is Elms Lea, the former Director’s Residence, a two-storey brick farmhouse. The historic place also features the Antenna Field, natural topographic rise, earthwork enhancements, designed landscaping, plantings, and experimental tree plantations. Official recognition refers to the boundaries of the David Dunlap Observatory Lands, designated under Part IV of the Ontario Heritage Act by the Town of Richmond Hill Designation By-law 100-09, covering an area of 40 hectares.

Heritage Value

David Dunlap Observatory was designated a National Historic Site of Canada in 2019. It is recognized because:

• when it opened in 1935 in what was an isolated setting, it featured the world’s second-largest telescope and was central to establishing academic astronomy in Canada. The long-term project of Clarence Augustus Chant, “the father of Canadian astronomy,” the Observatory was home to generations of astronomers at the University of Toronto, combining a mandate of teaching, research, and public accessibility;
• Through his research at the David Dunlap Observatory, astronomer Thomas Bolton achieved a major astronomical breakthrough when his research confirmed the existence of black holes in 1971;
• named in memory of David Dunlap and financed by Jessie Donalda Dunlap, the Observatory comprises two principal buildings: the Great Telescope Dome, a fine and well-preserved example of early to mid-20th century observatory design in Canada which successfully combines Modern and Neo-Classical elements; and the elegant Beaux-Arts Administration Building, designed by the architecture firm of Mathers & Haldenby, and in keeping with other designs for buildings for the University of Toronto.

The Observatory Dome still houses the largest optical telescope in the country and is a significant scientific artifact. C. A. Chant, a keystone in the inception of academic astronomy in Canada, championed its construction for decades, even securing the patronage of Jessie Donalda Dunlap, one of the few women to have endowed a major scientific and astronomical project in Canada. Her participation transformed the project from a relatively modest proposal to something much more ambitious. Construction of the Observatory made possible the development of astronomical research in Canada, which had previously been a limited field with few resources, into a point of national pride. Prior to its construction, no universities in Canada trained students in practical astronomy, and Chant aimed to solve this via the Observatory. With it, the University of Toronto offered the first graduate degrees in astronomy in Canada, where students learned from the leaders in the field. Over its decades of service as a University of Toronto facility, it spurred public research, helped sustain education in astronomy while its world-class research and training facilities were home to several generations of Canadian astronomers. Sold in 2008 due to the light pollution from the expansion of Toronto, it still serves as a community learning space.

Source: Historic Sites and Monuments Board of Canada, Minutes, December, 2018.

Character-Defining Elements

Key elements contributing to the heritage value of this site include:

- its location on a point of land in Richmond Hill, Ontario, rising 30 metres above the surrounding countryside, 240 metres above sea level, and approximately 19.31 kilometres from the main St. George campus of the University of Toronto;
- the site’s scientific purpose signalled by the massive dome of the Observatory Building and the secondary domes on the Administration Building;
- the Administration Building’s location at the end of a long sweeping driveway, the elliptical turnaround, and the straight pathway to the Observatory Building 40 metres away, that links the two structures;
- the Classical-inspired domed structure of the Observatory Building and 74 inch reflecting telescope within, the flat seam copper panels, the dome’s raised retractable shutters, the louvred window shutters, the pilasters, the metal catwalks, ladders, and stairs that envelope the exterior, the curving façade, and projecting entrance vestibule with double-leaved panelled door and bright blue geometric transom which contrasts with the white dome and façade;
- the Observatory building’s surviving interior original materials including the telescope, and its subsidiary scientific instruments, the spectrography room and darkroom, the clock, the mirror polishing equipment, the blue-painted curving staircase and doors and surrounds;
- the Administrative Building’s Beaux-Arts aesthetic seen in: the symmetrical façade with central entrance; the grey ashlar sandstone with silver-grey limestone cornices, string courses, quoins, window and door surrounds and other decorative facets; the double-height memorial entrance hall; the strong east-west axis off of the central hall, the two wings of double-loaded corridors; and the arched and circular windows;
- surviving interior original materials of the Administration Building such as the ornamental compass in the terrazzo floor, the memorial tablet, the travertine marble walls and stair treads, wrought-iron railing and details and belt courses in a Greek key motif;
- surviving scientific facilities of the Administration Building including the darkroom, laboratories, offices, lecture halls, the library, and machine shop, as well as the domed telescope turrets and the functioning telescope;
- the single-storey wood-frame Radio Shack;
- the red brick Elms Lea farmhouse;
- campus landscape features including: the Antenna Field; planted tree cover along Bayview Avenue; plantings around the Administration Building, the row of trees along the front; the elliptical island within the driveway with paving designed to evoke Kepler’s 2nd Law of Planetary Motion; the straight paved path leading to the Observatory Building entrance; and the sundial.