James Bradley was an English astronomer best known for his discovery of the aberration of light and of the nutation of the earth's axis.
Born in March 1693 and baptised on 3 October the same year, both in Sherborne, Gloucestershire, James attended Westwood's Grammar School at Northleach, before attending Balliol College, Oxford, where he was admitted as a commoner, that is a student who does not have a scholarship. * However, James's career with the church was not to be long-lived. * The most significant of Bradley's early years, when considering his later career in astronomy, were those spent in contact with his maternal uncle, the Reverend James Pound, a leading astronomical observer in England, who had worked with Edmond Halley and Sir Isaac Newton. * It was through this uncle that James would meet Halley. * By 1715, James Bradley had joined his uncle James Pound in carrying out astronomical observations. * Pound provided Bradley with occasional financial assistance, and is credited with influencing Bradley's interests towards astronomy. * Despite Pound's death in November 1724, Bradley continued to use his uncle's observatory at Wansted. * Though no will was left, Bradley maintained his usage of the same instruments, and residence with Pound's widow. * Having previously written to the Royal Society in March 1716 about the aurora, two of Bradley's observations were published by Halley in 1718 in the Philosophical Transactions of the Royal Society. * Halley praised Bradley's abilities and, in November 1718, Bradley was elected a fellow of the Royal Society on Halley's recommendation. * Bradley was best known for two important discoveries in astronomy: the aberration of light and the nutation of the Earth's axis. * As a friend of Samuel Molyneux, who was interested in measuring the annual parallax of stars, from which it would be possible to calculate the distances to the nearest stars, Bradley was invited by Molyneux in December 1725 to his estate at Kew, a district of London, to assist him in observing the star Gamma Draconis, specifically, attempting to determine its annual parallax. * Bradley thus, from August 1727, in an attempt to explain the cause of this movement, decided to observe a number of stars over the year. * Bradley suggested that analogously, the apparent shift in the position observed in the stars was a result of of a combination of the transmission of light at a finite speed from the star and the annual movement of the Earth around the Sun. * The letter from Bradley to Halley referencing this phenomenon was read to the Royal Society in January 1729. * The year 1732 saw Bradley move to Oxford to occupy a house in New College Lane, to which his professorship entitled him. * His aunt, widow of James Pound, stayed with him until her death in 1737. * Bradley made frequent return visits to Wansted to use it. * Continuing his observations at Wansted after he moved to Oxford, Bradley aimed to collect evidence he was observing of the nutation of the Earth's polar axis. * Bradley proved his dedication to the problem by pursuing his observations, despite a major hurdle: the Earth's axis would take more than 18 years to complete a nutational cycle. * By this time, however, there was also separate observational confirmation by French expeditions to Sweden and Peru, but Bradley's work here, and his earlier work on aberration, added to the increasing evidence for a heliocentric solar system. * It was thus that Bradley was awarded the Royal Society's Copley medal in 1748. * Bradley served as Astronomer Royal from 1742, the third to occupy the role, succeeding Halley. * It was she who would inherit the Greenwich observations her father had made over the 20 years prior to his death, the same observations, that for many reasons, were not published for over 30 years after Bradley's death. * It was not until 1798 that any of Bradley's observations were published. * It took 10 years of Bessel's work, which began with Bradley's observations, resulting in his Fundamenta astronomia Ⓣ(Fundamental astronomy) (1818), lauded as one of the most significant works on positional astronomy. * Bradley's influence extended into the 20th century, with three volumes of his observations being published between 1882 and 1903. * It has been suggested that with these, Bradley had laid the foundation of all modern star positions. * Bradley collected data sent to him from London and Jamaica, and, allowing for the temperature differences, concluded that the clock used for these experiments slowed by about 2 minutes per day when in Jamaica in comparison to when in London. * Moreover, though not documented, it is believed that Bradley, as Astronomer Royal, had a role in England's adoption of the Gregorian calendar in 1752. * It was to be his poor health that would force Bradley into retirement in 1761. * Highly regarded during his lifetime, and recognised by some of the greats of the day, James Bradley was highly influential in the advancement of astronomical thinking.
Born in March 1693 and baptised on 3 October the same year, both in Sherborne, Gloucestershire, James attended Westwood's Grammar School at Northleach, before attending Balliol College, Oxford, where he was admitted as a commoner, that is a student who does not have a scholarship. * However, James's career with the church was not to be long-lived. * The most significant of Bradley's early years, when considering his later career in astronomy, were those spent in contact with his maternal uncle, the Reverend James Pound, a leading astronomical observer in England, who had worked with Edmond Halley and Sir Isaac Newton. * It was through this uncle that James would meet Halley. * By 1715, James Bradley had joined his uncle James Pound in carrying out astronomical observations. * Pound provided Bradley with occasional financial assistance, and is credited with influencing Bradley's interests towards astronomy. * Despite Pound's death in November 1724, Bradley continued to use his uncle's observatory at Wansted. * Though no will was left, Bradley maintained his usage of the same instruments, and residence with Pound's widow. * Having previously written to the Royal Society in March 1716 about the aurora, two of Bradley's observations were published by Halley in 1718 in the Philosophical Transactions of the Royal Society. * Halley praised Bradley's abilities and, in November 1718, Bradley was elected a fellow of the Royal Society on Halley's recommendation. * Bradley was best known for two important discoveries in astronomy: the aberration of light and the nutation of the Earth's axis. * As a friend of Samuel Molyneux, who was interested in measuring the annual parallax of stars, from which it would be possible to calculate the distances to the nearest stars, Bradley was invited by Molyneux in December 1725 to his estate at Kew, a district of London, to assist him in observing the star Gamma Draconis, specifically, attempting to determine its annual parallax. * Bradley thus, from August 1727, in an attempt to explain the cause of this movement, decided to observe a number of stars over the year. * Bradley suggested that analogously, the apparent shift in the position observed in the stars was a result of of a combination of the transmission of light at a finite speed from the star and the annual movement of the Earth around the Sun. * The letter from Bradley to Halley referencing this phenomenon was read to the Royal Society in January 1729. * The year 1732 saw Bradley move to Oxford to occupy a house in New College Lane, to which his professorship entitled him. * His aunt, widow of James Pound, stayed with him until her death in 1737. * Bradley made frequent return visits to Wansted to use it. * Continuing his observations at Wansted after he moved to Oxford, Bradley aimed to collect evidence he was observing of the nutation of the Earth's polar axis. * Bradley proved his dedication to the problem by pursuing his observations, despite a major hurdle: the Earth's axis would take more than 18 years to complete a nutational cycle. * This letter gives a wonderful understanding of how Bradley worked and his ways of thinking and we have made available the first part of that letter at THIS LINK. * By this time, however, there was also separate observational confirmation by French expeditions to Sweden and Peru, but Bradley's work here, and his earlier work on aberration, added to the increasing evidence for a heliocentric solar system. * It was thus that Bradley was awarded the Royal Society's Copley medal in 1748. * Bradley served as Astronomer Royal from 1742, the third to occupy the role, succeeding Halley. * It was she who would inherit the Greenwich observations her father had made over the 20 years prior to his death, the same observations, that for many reasons, were not published for over 30 years after Bradley's death. * It was not until 1798 that any of Bradley's observations were published. * It took 10 years of Bessel's work, which began with Bradley's observations, resulting in his Fundamenta astronomia Ⓣ(Fundamental astronomy) (1818), lauded as one of the most significant works on positional astronomy. * For Stephen Peter Rigaud's Preface to Miscellaneous works and correspondence of the Rev James Bradley, D.D. F.R.S. (Oxford University Press, Oxford, 1832), see THIS LINK. * Bradley's influence extended into the 20th century, with three volumes of his observations being published between 1882 and 1903. * It has been suggested that with these, Bradley had laid the foundation of all modern star positions. * Bradley collected data sent to him from London and Jamaica, and, allowing for the temperature differences, concluded that the clock used for these experiments slowed by about 2 minutes per day when in Jamaica in comparison to when in London. * Moreover, though not documented, it is believed that Bradley, as Astronomer Royal, had a role in England's adoption of the Gregorian calendar in 1752. * It was to be his poor health that would force Bradley into retirement in 1761. * Highly regarded during his lifetime, and recognised by some of the greats of the day, James Bradley was highly influential in the advancement of astronomical thinking.
Born March 1693, Sherborne, Gloucestershire, England. Died 13 July 1762, Chalford, Gloucestershire, England.
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Astronomy, Origin England, Physics
