John Stanley Plaskett (November 17, 1865 – October 17, 1941) was a

Canadian Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either ...

Career

He worked as a machinist, and was offered a job as a mechanician at the Department of

Physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

at the

University of Toronto The University of Toronto (UToronto or U of T) is a public university, public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park (Toronto), Queen's Park. It was founded by royal charter in 1827 ...

, constructing apparatus and assisting with demonstrations during lectures. He found this so interesting that at the age of 30 he enrolled as an undergraduate in mathematics and physics. He stayed at the university until 1903, doing research on color photography. His formal astronomical career did not start until 1903, when he was appointed to the staff at

Dominion Observatory The Dominion Observatory was an astronomical observatory in Ottawa, Ontario that operated from 1902 to 1970. The Observatory was also an institution within the Canadian Federal Government. The observatory grew out of the Department of the Inter ...

Ottawa, Ontario Ottawa (, ; Canadian French: ) is the capital city of Canada. It is located at the confluence of the Ottawa River and the Rideau River in the southern portion of the province of Ontario. Ottawa borders Gatineau, Quebec, and forms the core ...

. He measured

radial velocities The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the rate of change of the distance or range between the two points. It is equivalent to the vector projection o ...

and studied

spectroscopic binaries A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in w ...

, and performed the first detailed analysis of galactic structure. His mechanical background was very useful for constructing various instruments. He became first director of the

Dominion Astrophysical Observatory The Dominion Astrophysical Observatory, located on Observatory Hill, in Saanich, British Columbia, was completed in 1918 by the Canadian government. The Dominion architect responsible for the building was Edgar Lewis Horwood. The main instrument ...

Victoria, British Columbia Victoria is the capital city of the Canadian province of British Columbia, on the southern tip of Vancouver Island off Canada's Pacific coast. The city has a population of 91,867, and the Greater Victoria area has a population of 397,237. The ...

in 1917 (not to be confused with the old

in Ottawa). Delegates to the Fourth Conference International Union for Cooperation in Solar Research at Mount Wilson Observatory

Family and legacy

His son, Harry Hemley Plaskett, also pursued a very successful career in astronomy, winning the

Gold Medal of the Royal Astronomical Society The Gold Medal of the Royal Astronomical Society is the highest award given by the Royal Astronomical Society (RAS). The RAS Council have "complete freedom as to the grounds on which it is awarded" and it can be awarded for any reason. Past awar ...

in 1963, thereby making the Plasketts one of the very few families to boast more than one Medal winner. An authoritative biography of JS Plaskett was published in 2018, coinciding with the centennial of the

Honours

Awards

(1930) *

Rumford Prize Founded in 1796, the Rumford Prize, awarded by the American Academy of Arts and Sciences, is one of the oldest scientific prizes in the United States. The prize recognizes contributions by scientists to the fields of heat and light. These terms ...

(1930) *

Bruce Medal The Catherine Wolfe Bruce Gold Medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. It is named after Catherine Wolfe Bruce, an American patroness of astronomy, and was fi ...

(1932) *

Henry Draper Medal The Henry Draper Medal is awarded every 4 years by the United States National Academy of Sciences "for investigations in astronomical physics". Named after Henry Draper, the medal is awarded with a gift of USD $15,000. The medal was established ...

from the National Academy of Sciences (1934) *

CBE The Most Excellent Order of the British Empire is a British order of chivalry, rewarding contributions to the arts and sciences, work with charitable and welfare organisations, and public service outside the civil service. It was established o ...

Named after him

*NRC-HIA Plaskett Fellowship *The crater Plaskett on the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

*Mount Plaskett *the Plaskett Medal *Asteroid 2905 Plaskett (with his son H.H. Plaskett) * Plaskett's star *Plaskett Place (street on which he built his home, in

Esquimalt, British Columbia The Township of Esquimalt is a municipality at the southern tip of Vancouver Island, in British Columbia, Canada. It is bordered to the east by the provincial capital, Victoria, to the south by the Strait of Juan de Fuca, to the west by Esquim ...

)

References

External links

Obituaries

MNRAS 102 (1942) 70

(one paragraph)

{{DEFAULTSORT:Plaskett, John Stanley 1865 births 1941 deaths 20th-century Canadian astronomers University of Toronto alumni Fellows of the Royal Society of Canada Canadian Commanders of the Order of the British Empire Recipients of the Gold Medal of the Royal Astronomical Society Persons of National Historic Significance (Canada) Canadian Fellows of the Royal Society Fellows of the American Physical Society