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

Canadian Canadians () 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 their being ''C ...

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

Career

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

Physics Physics is the scientific study of matter, its Elementary particle, 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 whi ...

at the

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

, 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 Inte ...

Ottawa, Ontario Ottawa is the capital city of Canada. It is located in the southern Ontario, southern portion of the province of Ontario, at the confluence of the Ottawa River and the Rideau River. Ottawa borders Gatineau, Gatineau, Quebec, and forms the cor ...

. He measured

radial velocities The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity on ...

and studied

spectroscopic binaries A binary star or binary star system is a Star system, system of two stars that are gravity, 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 ...

, 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 (Saanich), Observatory Hill, in Saanich, British Columbia, was completed in 1918 by the Canadian Government, Canadian government. The Dominion architect responsible for the bui ...

Victoria, British Columbia Victoria is the capital city of the Provinces and territories of Canada, Canadian province of British Columbia, on the southern tip of Vancouver Island off Canada's Pacific Ocean, Pacific coast. The city has a population of 91,867, and the Gre ...

in 1917 (not to be confused with the old

Ottawa Ottawa is the capital city of Canada. It is located in the southern Ontario, southern portion of the province of Ontario, at the confluence of the Ottawa River and the Rideau River. Ottawa borders Gatineau, Gatineau, Quebec, and forms the cor ...

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 ...

(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 The National Academy of Sciences (NAS) is a United States nonprofit, NGO, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the ...

(1934) *

CBE The Most Excellent Order of the British Empire is a British order of chivalry, rewarding valuable service in a wide range of useful activities. It comprises five classes of awards across both civil and military divisions, the most senior two o ...

Honors

* Elected International Member of the

American Philosophical Society The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publicat ...

(1930)

Named after him

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

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

*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, British Columbia, Victoria, to the south by the Strait of Jua ...

)

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 International members of the American Philosophical Society