Leon Campbell

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Leon Campbell (January 20, 1881 – May 10, 1951) [1] was an American astronomer.

United States Federal republic in North America

The United States of America (USA), commonly known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is slightly smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico. The State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean. The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The extremely diverse geography, climate, and wildlife of the United States make it one of the world's 17 megadiverse countries.

Astronomer scientist who studies celestial bodies

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 observational or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, solar astronomy, the origin or evolution of stars, or the formation of galaxies. Related but distinct subjects like physical cosmology, which studies the Universe as a whole.

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He is noted for his observations of variable stars at the Harvard College Observatory. He served as Recorder of Observations for the AAVSO from its earliest days in 1915, and continued until his retirement in the 1940s. (The title was later changed to Director of the AAVSO.) He also published a number of papers and a pair of books on the topic of variable stars.

Variable star star whose brightness as seen from Earth fluctuates

A variable star is a star whose brightness as seen from Earth fluctuates.

Harvard College Observatory observatory

The Harvard College Observatory (HCO) is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Harvard University Department of Astronomy. It is located in Cambridge, Massachusetts, USA, and was founded in 1839. With the Smithsonian Astrophysical Observatory, it forms part of the Harvard–Smithsonian Center for Astrophysics.

Awards and honors

Campbell (lunar crater) impact crater

Campbell is a large lunar impact crater that is located in the northern hemisphere on the far side of the Moon. It lies to the southwest of the walled plain D'Alembert, an even larger formation. If Campbell were located on the near side of the Moon as seen from the Earth, it would form one of the largest visible craters, being slightly larger than Schickard. It is bordered by several craters of note, with Wiener to the southwest, Von Neumann just to the south, Ley overlying the southeast rim, and Pawsey to the west.

William Wallace Campbell American astronomer

William Wallace Campbell was an American astronomer, and director of Lick Observatory from 1901 to 1930. He specialized in spectroscopy.

Bibliography

Related Research Articles

Since its founding in 1911, the American Association of Variable Star Observers (AAVSO) has coordinated, collected, evaluated, analyzed, published, and archived variable star observations made largely by amateur astronomers and makes the records available to professional astronomers, researchers, and educators. These records establish light curves depicting the variation in brightness of a star over time.

Leslie Copus Peltier was an American amateur astronomer and discoverer of several comets and novae, once described as "the world's greatest non-professional astronomer" by Harlow Shapley.

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William Tyler Olcott (1873–1936) was an American lawyer and amateur astronomer.

RV Tauri variable type of variable star

RV Tauri variables are luminous variable stars that have distinctive light variations with alternating deep and shallow minima.

Flarestar Observatory

Flarestar Observatory is an astronomical observatory owned and operated and managed by astronomer and AAVSO-member Stephen M. Brincat. It is located near San Ġwann on the island country of Malta.

Margaret Walton Mayall was an American astronomer. She was the director of the American Association of Variable Star Observers (AAVSO) from 1949 to 1973.

U Geminorum star

U Geminorum, in the constellation Gemini, is an archetypal example of a dwarf nova. The binary star system consists of a white dwarf closely orbiting a red dwarf. Every few months it undergoes an outburst that greatly increases its brightness. The dwarf nova class of variable stars are often referred to as U Geminorum variables after this star.

Michiel Daniel Overbeek, also known as Danie Overbeek, was a South African amateur astronomer and one of the most prolific variable star observers.

Edward A. Halbach American amateur astronomer

Edward A. Halbach was an American amateur astronomer and prolific variable star observer.

Radha Gobinda Chandra Bangladeshi-Indian astronomer

Radhagobinda Chandra was a Bangladeshi-Indian astronomer. He was a pioneer of observational astronomy in the region of Bengal, comprising modern-day Bangladesh and West Bengal. He was born in Bangladesh when this country was a part of British India. Radha Gobinda is especially famous for his observation of variable stars. He observed more than 49,700 variable stars and became one of the first international members of American Association of Variable Star Observers.

S Coronae Borealis star

S Coronae Borealis is a Mira variable star in the constellation Corona Borealis. Its apparent magnitude varies between 5.8 and 14.1, with a period of 360 days—just under a year. Within the constellation, it lies to the west of Theta Coronae Borealis, and around 1 degree southeast of the eclipsing binary star U Coronae Borealis.

8900 AAVSO, provisional designation 1995 UD2, is a stony background asteroid from the central region of the asteroid belt, approximately 5.5 kilometers in diameter. It was discovered by American amateur astronomer Dennis di Cicco at the U.S Sudbury Observatory (817), Massachusetts, on 24 October 1995. The asteroid was named after the American Association of Variable Star Observers (AAVSO).

U Scorpii Recurrent nova

U Scorpii is a recurrent nova system; one of 10 known recurring novae in the Milky Way galaxy. Located near the northern edge of the constellation Scorpius it normally has a magnitude of 18, but reaches a magnitude of about 8 during outbursts. Outbursts have been observed in 1863, 1906, 1936, 1979, 1987, 1999, and 2010.

Phoebe Waterman Haas was one of the earliest American woman to be awarded a doctorate in Astronomy (1913). While her formal professional career ended upon her marriage, she contributed as a citizen scientist, volunteering for the American Association of Variable Star Observers (AAVSO). The Phoebe Waterman Haas Public Observatory was supported by donations from her family and is named in her honor.

John E. Bortle is an American amateur astronomer. He is best known for creating the Bortle scale to quantify the darkness of the night sky.

References

  1. ↑ Hockey, Thomas (2009). The Biographical Encyclopedia of Astronomers. Springer Publishing. ISBN   978-0-387-31022-0 . Retrieved August 22, 2012.


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