Nicholson, Seth B. (Seth Barnes), 1891-1963

Alternative names
Birth 1891-11-12
Death 1963-07-02

Biographical notes:

Seth Barnes Nicholson was born in Springfield, Illinois on November 21, 1891. He received his Bachelors in Science from Drake University, Des Moines Indiana in 1911 and his Ph.D. from the University of California in 1914. He discovered Sinope, the ninth moon of Jupiter, while observing the seventh moon, Pasiphaë, at Lick Observatory. The computation of its orbit was the subject of his Ph.D. thesis. Nicholson went on to discover three other moons of Jupiter, along with two asteroids, during his decades' long career at the Wilson Observatory. His main focus at Wilson Observatory was to monitor solar activity and he wrote the annual sunspot activity reports for most of his career. He made significant discoveries regarding sunspots, especially in regards to their magnetic properties and terrestrial effects. Nicholson served as the editor of the Publications of the Astronomical Society of the Pacific from 1943 to 1955 and was twice the president of the society. He was awarded the Bruce Medal in 1963, the year he died in Los Angeles.

From the description of Papers of Seth Barnes Nicholson, 1914-1963. (Huntington Library, Art Collections & Botanical Gardens). WorldCat record id: 712919209


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  • Astronomers--Archives
  • Astronomy--Photographs
  • Astronomy--Research
  • Astronomical observatories
  • Asteroids
  • Astronomy--History--20th century--Sources
  • Sunspots


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  • Icarus (Asteroid) (as recorded)
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  • Pluto (Dwarf planet) (as recorded)
  • California--Wilson, Mount (Mountain) (as recorded)
  • Venus (Planet) (as recorded)
  • Jupiter (Planet) (as recorded)