John Stanley Plaskett

John Stanley Plaskett

John Stanley Plaskett, astronomer (b at Hickson, UC 17 Nov 1865; d at Esquimalt, BC 17 Oct 1941). Born on a farm, Plaskett joined the Edison Co in Schenectady, New York, and Sherbrooke, Québec. Foreman of the workshop in the department of physics at University of Toronto in 1890, he enrolled as a student in 1895 and graduated in 1899. In 1903 Plaskett joined the astronomical branch of the Department of the Interior, Ottawa, helping to design and construct instruments for the new Dominion Observatory there. He observed a solar eclipse in 1905 and did important work on radial velocities of stars. His proposal for a large telescope was approved and the 72-inch (1.8 m) telescope (then the world's largest) was completed in 1918 at Victoria, BC. Plaskett became the first director there, retiring in 1935. He worked on spectroscopic binaries (a massive one that he discovered still bears his name) and together with J.A. PEARCE published the first detailed analysis of the structure of the Milky Way Galaxy (1935). They demonstrated that the sun is two-thirds out from the centre of our galaxy and rotates once in 220 million years. In 1984 Minor Planet No 2905 was named Plaskett in honour of J.S. Plaskett and his son H.H. Plaskett, also an astronomer.