This Week in History


The Stars Reveal Their Secrets

For the week of Monday November 12, 2012

 On November 17, 1865, John Stanley Plaskett was born. The world-renowned Canadian astronomer lobbied for the construction of the Dominion Astrophysical Observatory, which became a genuine centre of excellence in astrophysics research.

Born near Woodstock, Ontario, Plaskett first worked as a mechanic for the Edison Company before moving to the Department of Physics at the University of Toronto. It was there that he discovered a passion for physics and, at the age of 30, began a bachelor’s degree in math and physics. His career as an astrophysicist was launched in 1903, when he was invited to join the Dominion Observatory’s team in Ottawa because of his theoretical and practical knowledge.

Dominion Astrophysical Observatory
© Library and Archives Canada / Albertype Company / PA-032169
During his time at the Dominion Observatory, John Plaskett published a number of reports on binary stars (two stars orbiting each other). However, his work was hindered by the limitations of the telescope. In 1912, grants were awarded to finance the construction of a new observatory, which would be headed up by Plaskett. After a series of tests to find the best location, he decided to locate the observatory in Saanich, British Columbia, at the top of a hill 227 metres above sea level. It was named the Dominion Astrophysical Observatory.

The construction of the Observatory, from 1914 to 1918, proved to be a feat of engineering. The cylindrical structure, which is approximately 20 metres in diameter and 22 metres high, is topped by a domed roof imported from the United States that weighs several tons and can open for observations of the sky. The Observatory was built according to the most modern designs of the period and is very attractive, featuring classically inspired architectural embellishments.

Commemorative stamp featuring the horsehead nebula and the Dominion Astrophysical Observatory
© Canada Post Corporation / 2009
John Plaskett, the Observatory’s director, designed its main instruments and played a role in improving the new 1.83-metre telescope, the most advanced in the world at the time. It was at the Observatory that this important astrophysicist discovered the most massive binary star observed to that point. He served as the director until his retirement in 1935 and died in October 1941.

The Observatory is world-renowned for the many discoveries about the nature of the Milky Way that have been made there, and the collaborative research carried out with other observatories; it has also welcomed many well-known Canadian and foreign astronomers. It was one of the world’s main astrophysical research centres until 1960, and today its telescope is still used every evening for research purposes.

As a result of his many discoveries in astrophysics and his importance as the director of the Dominion Astrophysical Observatory, John Stanley Plaskett was designated a person of national historic significance in 1949. The Dominion Astrophysical Observatory was designated a place of national historic significance in 2008 for its contribution to astrophysics.

To learn more about the history of astronomy in Canada, read One Very Scholarly Scot! in the archives of This Week in History.

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