John Stanley Plaskett
John Stanley Plaskett (November 17, 1865 – October 17, 1941) was a Canadian astronomer. He was born in Hickson, Canada West, and started his career as a machinist. He then worked as a mechanician at the University of Toronto, building equipment and helping with demonstrations. The work sparked his interest in science, and at age 30 he enrolled as an undergraduate in mathematics and physics. He stayed at the university until 1903, researching color photography.
His astronomy career began in 1903 at the Dominion Observatory in Ottawa, where he measured the radial velocities of stars and studied spectroscopic binaries. He carried out the first detailed analysis of the structure of the Milky Way, and his mechanical skills helped him build special instruments.
In 1917 he became the first director of the Dominion Astrophysical Observatory in Victoria, British Columbia (not the Ottawa observatory).
His son, Harry Hemley Plaskett, also became a successful astronomer and won the Gold Medal of the Royal Astronomical Society in 1963, making the Plaskett family notable in astronomy.
A biography of Plaskett was published in 2018 to mark the centennial of the Dominion Astrophysical Observatory.
Plaskett received the Bruce Medal and the Flavelle Medal in 1932. He was also a Commander of the British Empire and a Fellow of the Royal Society.
This page was last edited on 2 February 2026, at 04:48 (CET).