Seth Carlo Chandler, Jr. (September 16, 1846 – December 31, 1913) was an American astronomer

Astronomer

An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...

.

He was born in Boston

Boston

Boston is the capital of and largest city in Massachusetts, and is one of the oldest cities in the United States. The largest city in New England, Boston is regarded as the unofficial "Capital of New England" for its economic and cultural impact on the entire New England region. The city proper had...

, Massachusetts

Massachusetts

The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...

. During his last year in high school he performed mathematical computations for Benjamin Peirce

Benjamin Peirce

Benjamin Peirce was an American mathematician who taught at Harvard University for approximately 50 years. He made contributions to celestial mechanics, statistics, number theory, algebra, and the philosophy of mathematics....

, of the Harvard College Observatory

Harvard College Observatory

The Harvard College Observatory 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...

.

After graduating, he became the assistant of Benjamin A. Gould. Gould was director of the Longitude Department of the U.S. Coast Survey program, a geodetic

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...

 survey program. When Gould left to become director of the national observatory in Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

, Chandler also left and became an actuary. However, he continued to work in astronomy as an amateur affiliated with Harvard College Observatory.

Chandler is best remembered for his research on what is today known as the Chandler wobble

Chandler wobble

The Chandler wobble is a small motion in the Earth's axis of rotation relative to the Earth's surface, which was discovered by American astronomer Seth Carlo Chandler in 1891. It amounts to on the Earth's surface and has a period of 433 days...

. His research on this spanned nearly three decades.

Chandler also made contributions to other areas of astronomy, including variable star

Variable star

A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...

s. He independently co-discovered the nova

Nova

A nova is a cataclysmic nuclear explosion in a star caused by the accretion of hydrogen on to the surface of a white dwarf star, which ignites and starts nuclear fusion in a runaway manner...

 T Coronae Borealis

T Coronae Borealis

T Coronae Borealis , informally nicknamed the Blaze Star, is a recurring nova in the constellation Corona Borealis. It normally has a magnitude of about 10, which is near the limit of typical binoculars. It has been seen to outburst twice, reaching magnitude 2.0 on May 12, 1866 and magnitude 3.0...

, improved the estimate of the constant of aberration, and computed the orbital parameters of asteroid

Asteroid

Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

s and comet

Comet

A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...

s.

Chandler was awarded the Gold Medal of the Royal Astronomical Society

Gold Medal of the Royal Astronomical Society

-History:In the early years, more than one medal was often awarded in a year, but by 1833 only one medal was being awarded per year. This caused a problem when Neptune was discovered in 1846, because many felt an award should jointly be made to John Couch Adams and Urbain Le Verrier...

 in 1896 and the James Craig Watson Medal

James Craig Watson Medal

thumb|right|400px|James Craig Watson MedalThe James Craig Watson Medal was established by the bequest of James Craig Watson, and is awarded by the U.S. National Academy of Sciences for contributions to astronomy.The recipients have been:-External links:*...

 in 1894.

The crater Chandler

Chandler (crater)

Chandler is a lunar crater that is located in the northern hemisphere, on the Moon's far side. It lies to the southeast of the large walled plain D'Alembert, and southeast of the slightly smaller crater Chernyshev....

 on the Moon

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 is named after him.

External links

• Biography (National Academy of Sciences)