Samuel Alfred Mitchell was an astronomer who studied solar eclipse

Solar eclipse

As seen from the Earth, a solar eclipse occurs when the Moon passes between the Sun and the Earth, and the Moon fully or partially blocks the Sun as viewed from a location on Earth. This can happen only during a new moon, when the Sun and the Moon are in conjunction as seen from Earth. At least...

s and set up a program to use photographic techniques to determine the distance to stars at McCormick Observatory

McCormick Observatory

The McCormick Observatory is one of the astronomical observatories operated by the Department of Astronomy of the University of Virginia and is situated just outside of Charlottesville, Virginia in Albemarle County on the summit of Mount Jefferson . It is named for Leander J...

, where he served as the director.

Early years

Mitchell was the son of John Cook and Sarah Chown Mitchell, the sixth of ten children to grow up in the Mitchell home. Mitchell's father (a tenth child) emigrated to Canada from St. Austell, Cornwall

Cornwall

Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...

. His mother, born in Kingston, was the tenth child of parents who emigrated to Canada from Devonshire. At age twelve Mitchell went off to Kingston Collegiate Institute. From there, he went on to Queen's University

Queen's University

Queen's University, , is a public research university located in Kingston, Ontario, Canada. Founded on 16 October 1841, the university pre-dates the founding of Canada by 26 years. Queen's holds more more than of land throughout Ontario as well as Herstmonceux Castle in East Sussex, England...

 where he received his Masters of Arts in mathematics in 1894. While at Queen's University, he acquired knowledge of the techniques of an astronomical observatory when he was asked to care for the astronomical instruments of the university.

Upon encouragement from his math professor, Nathan Dupuis, he left in 1895 for The Johns Hopkins University to study math under Simon Newcomb

Simon Newcomb

Simon Newcomb was a Canadian-American astronomer and mathematician. Though he had little conventional schooling, he made important contributions to timekeeping as well as writing on economics and statistics and authoring a science fiction novel.-Early life:Simon Newcomb was born in the town of...

, only to find Newcomb retired. Thomas Craig was the new head of mathematics and Mitchell also began study under Charles Lane Poor

Charles Lane Poor

Charles Lane Poor was an opponent of Einstein's theory of relativity.-Biography:He was born on January 18, 1866 in Hackensack, New Jersey to Edward Erie Poor. He graduated from the City College of New York and received a Ph.D. in 1892 from Johns Hopkins University...

, the head of astronomy. Poor was an excellent teacher and Mitchell was inclined to follow astronomy from that point on. Mitchell was awarded an astronomy assistantship for his second year at JHU and continued until he received his PhD in 1898 with his thesis published in the Astrophysical Journal

Astrophysical Journal

The Astrophysical Journal is a peer-reviewed scientific journal covering astronomy and astrophysics. It was founded in 1895 by the American astronomers George Ellery Hale and James Edward Keeler. It publishes three 500-page issues per month....

, which included a discussion of the amount of astigmatism

Astigmatism

An optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances...

 of a concave

Concave function

In mathematics, a concave function is the negative of a convex function. A concave function is also synonymously called concave downwards, concave down, convex upwards, convex cap or upper convex.-Definition:...

 grating

Grating

A grating is any regularly spaced collection of essentially identical, parallel, elongated elements. Gratings usually consist of a single set of elongated elements, but can consist of two sets, in which case the second set is usually perpendicular to the first...

. While at Hopkins, his astronomy duties consisted of caring for the astronomical transit

Astronomical transit

The term transit or astronomical transit has three meanings in astronomy:* A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, hiding a small part of it, as seen by an observer at some particular vantage point...

 instrument and the clocks in the little observatory behind the physics laboratory, and the 9.5-inch refractor in the dome of the laboratory roof.

Yerkes Observatory

Following receipt of his doctoral degree, Mitchell set out for the brand new Yerkes Observatory

Yerkes Observatory

Yerkes Observatory is an astronomical observatory operated by the University of Chicago in Williams Bay, Wisconsin. The observatory, which calls itself "the birthplace of modern astrophysics," was founded in 1897 by George Ellery Hale and financed by Charles T. Yerkes...

 in Wisconsin

Wisconsin

Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...

 where he began work as a research student in 1898. Though he enjoyed his work at Yerkes, he was enticed to move away and became an instructor in astronomy at Columbia University

Columbia University

Columbia University in the City of New York is a private, Ivy League university in Manhattan, New York City. Columbia is the oldest institution of higher learning in the state of New York, the fifth oldest in the United States, and one of the country's nine Colonial Colleges founded before the...

 in June 1899. Over the fourteen years he was at Columbia, Mitchell taught undergraduate courses in descriptive astronomy both at Columbia and later for girls from Barnard College

Barnard College

Barnard College is a private women's liberal arts college and a member of the Seven Sisters. Founded in 1889, Barnard has been affiliated with Columbia University since 1900. The campus stretches along Broadway between 116th and 120th Streets in the Morningside Heights neighborhood in the borough...

, a year long course in geodesy

Geodesy

Geodesy , also named geodetics, a branch of earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a three-dimensional time-varying space. Geodesists also study geodynamical phenomena such as crustal...

 for third year students, which continued into a first semester fourth year course, and a six week summer camp for civil engineers.

Eclipse work

In 1900, he took what would be for him the first of ten eclipse

Eclipse

An eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer...

 expeditions. The May 28, 1900 eclipse took him to Griffin, Georgia

Griffin, Georgia

Griffin is a city in and the county seat of Spalding County in the U.S. state of Georgia. It is part of the Atlanta metropolitan area. As of the 2010 census, the city had a population of 23,643.-Geography:Griffin is located at ....

 with the United States Naval Observatory

United States Naval Observatory

The United States Naval Observatory is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation, and Timing for the U.S. Navy and the U.S. Department of Defense...

. Mitchell became a world-renowned authority on solar eclipses through his numerous expeditions, including trips to: Sawah Loento, Sumatra

Sumatra

Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

 in the Dutch West Indies (May 18, 1901), Daroca, Spain

Spain

Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 (August 30, 1905), Baker, Oregon (June 8, 1918), San Diego, California

San Diego, California

San Diego is the eighth-largest city in the United States and second-largest city in California. The city is located on the coast of the Pacific Ocean in Southern California, immediately adjacent to the Mexican border. The birthplace of California, San Diego is known for its mild year-round...

 (September 10, 1923), Van Vleck Observatory

Van Vleck Observatory

Van Vleck Observatory is an astronomical observatory owned and operated by Wesleyan University. It was built in 1914 and named after the former head of the Department of Mathematics and Astronomy at the university, Prof. John M. Van Vleck. It is located in Middletown, Connecticut .-Directors:*...

, Middleton, Connecticut

Connecticut

Connecticut is a state in the New England region of the northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, and the state of New York to the west and the south .Connecticut is named for the Connecticut River, the major U.S. river that approximately...

 (January 24, 1925), Fagernas, Norway

Norway

Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

 (June 29, 1927), Niuafoou or "Tin-Can" Island, Tonga

Tonga

Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...

, in the South Pacific Ocean (October 22, 1930), Magog, Quebec

Magog, Quebec

Magog is a city in southeastern Quebec, Canada, about east of Montreal at the confluence of Lake Memphremagog--after which the city was named—with the Rivière aux Cerises and the Magog River...

, Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 (August 31, 1932), and Kanton Island

Kanton Island

Kanton Island , alternatively known as "Mary Island", "Mary Balcout's Island" or "Swallow Island", is the largest, northernmost, and as of 2007, the sole inhabited island of the Phoenix Islands, in the Republic of Kiribati. It is an atoll located in the South Pacific Ocean roughly halfway between...

, Kiribati

Kiribati

Kiribati , officially the Republic of Kiribati, is an island nation located in the central tropical Pacific Ocean. The permanent population exceeds just over 100,000 , and is composed of 32 atolls and one raised coral island, dispersed over 3.5 million square kilometres, straddling the...

 (June 8, 1937), this time as the scientific leader of a National Geographic Society

National Geographic Society

The National Geographic Society , headquartered in Washington, D.C. in the United States, is one of the largest non-profit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, the promotion of environmental and historical...

 Expedition. An article entitled "Nature's Most Dramatic Spectacle" by Mitchell appeared in the September 1938 edition of National Geographic Magazine

National Geographic Magazine

National Geographic, formerly the National Geographic Magazine, is the official journal of the National Geographic Society. It published its first issue in 1888, just nine months after the Society itself was founded...

. These ten expeditions allowed him to write Eclipses of the Sun, summarizing his work on solar flash spectra, first published in 1923 and produced through five editions (5th edition, 1951). On the 1918 Oregon and the 1925 Connecticut eclipses, Mitchell was accompanied by the artist Howard Russell Butler

Howard Russell Butler

Howard Russell Butler was an American painter and founder of the American Fine Arts Society. Butler also persuaded Andrew Carnegie to fund the construction of Carnegie Lake near Princeton University. Butler also designed a mansion, an astronomy hall and painted a solar eclipse for the U.S. Naval...

 (1856-1934), whose paintings of totality graced the old Hayden Planetarium

Hayden Planetarium

The Hayden Planetarium is a public planetarium, part of the Rose Center for Earth and Space of the American Museum of Natural History in New York City, currently directed by astrophysicist Dr. Neil deGrasse Tyson....

 of the American Museum of Natural History

American Museum of Natural History

The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...

 for many years.

Parallax work and Leander McCormick Observatory

Mitchell went back to Yerkes for the summers of 1909, 1910 and 1911 and then returned for a fifteen month sabbatical in 1912 and 1913. Frank Schlesinger

Frank Schlesinger

Frank Schlesinger was an American astronomer. His work concentrated on using photographic plates rather than direct visual studies for astronomical research.-Biography:...

 first demonstrated the technique of determining stellar parallaxes photographically at Yerkes in 1905, and Mitchell (along with Frederick Slocum) carried out research applying the technique, publishing their results in 1913. At that point, he was offered the directorship at the Leander McCormick Observatory at the University of Virginia

University of Virginia

The University of Virginia is a public research university located in Charlottesville, Virginia, United States, founded by Thomas Jefferson...

. Mitchell spent much of his time and energy as director coming up with funds for running the observatory and paying staff and graduate students. Mitchell started the use of photographic plates with the visual 26-inch refractor shortly after his arrival at the University of Virginia. He became well known for his work on stellar parallaxes and photometry. Dr. Mitchell was liked by faculty and students alike, known for helping to bring prestige to the University.

Society Memberships

Mitchell was elected Director Emeritus in 1945 with a wealth of academic and scientific honors attributed to him. He was a member of the following societies: National Academy of Sciences

United States National Academy of Sciences

The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...

 (elected in 1933, elected to council in 1940, awarded James Craig Watson

James Craig Watson

James Craig Watson was a Canadian-American astronomer born in the village of Fingal, Ontario Canada. His family relocated to Ann Arbor, Michigan in 1850....

 Medal in 1948), American Association for the Advancement of Science

American Association for the Advancement of Science

The American Association for the Advancement of Science is an international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsibility, and supporting scientific education and science outreach for the...

 (Vice-President in 1921), American Astronomical Society

American Astronomical Society

The American Astronomical Society is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC...

 (Vice-President 1925-1927), Royal Astronomical Society

Royal Astronomical Society

The Royal Astronomical Society is a learned society that began as the Astronomical Society of London in 1820 to support astronomical research . It became the Royal Astronomical Society in 1831 on receiving its Royal Charter from William IV...

 (fellow and associate), International Astronomical Union

International Astronomical Union

The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...

 (president of Commission on Solar Eclipses and Commission on Stellar Parallaxes and Proper Motions), American Association of University Professors

American Association of University Professors

The American Association of University Professors is an organization of professors and other academics in the United States. AAUP membership is about 47,000, with over 500 local campus chapters and 39 state organizations...

 (chairman of Committee A, on Academic Freedom and Tenure), American Philosophical Society

American Philosophical Society

The American Philosophical Society, founded in 1743, and located in Philadelphia, Pa., is an eminent scholarly organization of international reputation, that promotes useful knowledge in the sciences and humanities through excellence in scholarly research, professional meetings, publications,...

, and the American Academy of Arts and Sciences

American Academy of Arts and Sciences

The American Academy of Arts and Sciences is an independent policy research center that conducts multidisciplinary studies of complex and emerging problems. The Academy’s elected members are leaders in the academic disciplines, the arts, business, and public affairs.James Bowdoin, John Adams, and...

.

Family

In December, 1899, Mitchell married Milly Gray Dumble, the daughter of Professor E. T. Dumble who was then the State Geologist of Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

 and was later Consulting Geologist of the Southern Pacific Railroad

Southern Pacific Railroad

The Southern Pacific Transportation Company , earlier Southern Pacific Railroad and Southern Pacific Company, and usually simply called the Southern Pacific or Espee, was an American railroad....

, an expert in petroleum

Petroleum

Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

 production.

The Mitchells' son, Allan C. G. Mitchell (1902-1963), was chair of the Indiana University

Indiana University Bloomington

Indiana University Bloomington is a public research university located in Bloomington, Indiana, in the United States. IU Bloomington is the flagship campus of the Indiana University system. Being the flagship campus, IU Bloomington is often referred to simply as IU or Indiana...

 Physics Department from 1938-1963 and pioneered the creation of the IU Cyclotron

Cyclotron

In technology, a cyclotron is a type of particle accelerator. In physics, the cyclotron frequency or gyrofrequency is the frequency of a charged particle moving perpendicularly to the direction of a uniform magnetic field, i.e. a magnetic field of constant magnitude and direction...

 Facility in 1941 (one of the first in the world).

The Mitchells' granddaughter is the economist Alice Mitchell Rivlin

Alice Rivlin

Alice Mitchell Rivlin is an economist, a former U.S. Cabinet official, and an expert on the budget. She has served as the Vice Chairman of the Federal Reserve, the Director of the White House Office of Management and Budget, and the first Director of the Congressional Budget Office...

.