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The many lives of the Louis B. Stewart Observatory

The grinning jack-o’-lantern painted on its dome – they say students did it – masks a long and rich history for the building officially called the Louis B. Stewart Observatory, but better known as the University of Toronto’s Students’ Union building.


It is now a place where students get oriented and organized, about 145 years ago its stones housed a hotbed of scientific activity.

The Toronto Magnetic and Meteorological Observatory was the successor to Canada’s first magnetic observatory and scientific institution, built in 1840 opposite where the university’s Convocation Hall now stands. It shared its government-directed mission – to study fluctuations in the earth’s magnetic field – with just three other sites in the world.

The provincial government rebuilt and expanded the observatory in 1855. Designed by architects Frederic Cumberland and William Storm, it featured elegant, Venetian-inspired stonework and trios of graceful elongated, arched windows. Functionally, it served as Canada’s chief meteorological station and its official timekeeper (time being dependent on astronomical observations) and was used to help develop standard time. A high-quality telescope installed in 1882 was considered pivotal in the development of Canadian astronomy.

By the turn of the 20th century, the observatory’s work had become hampered by the city’s and the university’s growth. U of T took it over, demolished it, and, at the urging of professor Louis Stewart, rebuilt it in 1908 using the same stones (plus some new ones) at another location, opposite where the university’s Hart House is now. Had it not been moved, it would be the university’s oldest building.

Besides becoming a geodetic observatory – measuring the earth and its gravitational field – it housed the campus police and the university’s central switch-board. It was turned over to the Students Administrative Council in 1953. A plaque on its east face commemorates students who died in the 1989 Chinese democracy uprising, and U of T students periodically give the dome, now sealed, a new and different paint job.

“It’s a very charming building, one that a lot of people miss,” says Larry Wayne Richards, a U of T professor emeritus in architecture.

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