GALLEN, Edmund (Halley Edmond)( English astronomer and geophysicist.)
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Biography GALLEN, Edmund (Halley Edmond)
Born November 29, 1656 in Haggerstone near London. He graduated from Oxford University (1676). In 1676-1678 took part in the expedition to o.Sv. Helena, where he spent observing the southern sky and compiled the first catalog of southern stars, containing 341 objects. In 1682 established his own observatory in Islington (a district of London). In 1685-1699 he served as assistant Secretary of the Royal Society of London, in 1703 took the place of professor of geometry at Oxford University, in 1720 became director of the Greenwich Observatory - Royal Astronomer.
The most well known Halley's achievements - the establishment of the method of calculating cometary orbits and the opening of the periodicity of certain comets. After laborious calculations, he concluded that the bright comet 1531, 1607 and 1682 - are one and the same object with a period of revolution around the Sun about 75 years and that the comet should reappear in the sky in 1758. December 25, 1785 German amateur astronomer I. Palic actually observed this comet, which has since been named Halley.
Among other discoveries Halley - Develop a method for determining the distance from Earth to the Sun on the results of observations of the passage of the inner planets of the solar disk. In 1677, Halley observed a transit of Mercury, has developed a method for observing transits of Venus in 1761 and 1769. In 1718, comparing their data on the position of stars with their coordinates listed in the catalog of Ptolemy, otnaruzhil proper motion of several stars - Arcturus, Procyon and Sirius. In 1722 began a program of positional observations of the Moon, whose results are used to accurately determine its orbit.
In his works on mathematics Halley proposed methods for calculating logarithms and trigonometric functions, created a geometric methods for solving numerical equations.
Halley was the first to conduct research on geophysics. In 1686 published his paper on trade winds and monsoons with an explanation of their causes. Halley studied the problem of Terrestrial Magnetism, built a model of Earth's magnetic field, was the first map of magnetic declinations.
The greatest merit of the scientist to the world of science is that it contributed to the emergence of work of Isaac Newton's Beginning (Principia). Halley not only managed to persuade Newton to write this work, but also published it on their own personal funds. Halley died in Greenwich on Jan. 14, 1742.