History of Astronomy |
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Page 3
... Hipparchus , about 150 B.C. , and Ptolemy a little later , were able to use the observations of Chaldæan astrologers , as well as those of Alexandrian astro- nomers , and to make some discoveries which have helped the progress of ...
... Hipparchus , about 150 B.C. , and Ptolemy a little later , were able to use the observations of Chaldæan astrologers , as well as those of Alexandrian astro- nomers , and to make some discoveries which have helped the progress of ...
Page 18
... Hipparchus ( 190-120 B.C. ) may be regarded as the founder of observational astronomy . He measured the obliquity of the ecliptic , and agreed with Eratosthenes . He altered the length of the tropical year from 365 days , 6 hours to 365 ...
... Hipparchus ( 190-120 B.C. ) may be regarded as the founder of observational astronomy . He measured the obliquity of the ecliptic , and agreed with Eratosthenes . He altered the length of the tropical year from 365 days , 6 hours to 365 ...
Page 19
... Hipparchus observed a new star . This upset every notion about the permanence of the fixed stars . He then set to work to catalogue all the principal stars so as to know if any others appeared or disappeared . Here his experiences ...
... Hipparchus observed a new star . This upset every notion about the permanence of the fixed stars . He then set to work to catalogue all the principal stars so as to know if any others appeared or disappeared . Here his experiences ...
Page 20
... Hipparchus was also the inventor of trigonometry , both plane and spherical . He explained the method of using eclipses for determining the longitude . In connection with Hipparchus ' great discovery it may be mentioned that modern ...
... Hipparchus was also the inventor of trigonometry , both plane and spherical . He explained the method of using eclipses for determining the longitude . In connection with Hipparchus ' great discovery it may be mentioned that modern ...
Page 22
George Forbes. of the universe . He adopted the excentric and equant of Hipparchus to explain the unequal motions of the sun and moon . He adopted the epicycles and deferents which had been used by Apollonius and others to explain the ...
George Forbes. of the universe . He adopted the excentric and equant of Hipparchus to explain the unequal motions of the sun and moon . He adopted the epicycles and deferents which had been used by Apollonius and others to explain the ...
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Common terms and phrases
accurate observations Airy astro Astronomer Royal Astronomia Nova astronomical units attraction axis bright calculations Cape Cassini catalogue centre century comet compute Copernicus diameter discovered discovery earth eclipse epicycles equatoreal error excentric explain fact fixed stars Galileo Greenwich Halley heavenly bodies heavens heliometer Hipparchus Huggins hydrogen hypothesis instruments Johann Kepler John Herschel Jupiter Jupiter's Kepler Laplace Lick Observatory light line of apses line of sight lunar Mars mathematical mean distance mean motion measured Mercury meteor method miles a second moon moon's nebulæ Newton Observatory orbit parallax perihelion period photographic physical planet planetary pole position predicted proper motion proved Ptolemy R. S. Phil records refractor retrograde retrograde motion revolution revolve round ring rotation round the sun satellites seems showed Sirius solar system spectra spectroscope spectrum spots stellar sun-spots sun's surface supposed tables telescope theory tion Trans Tycho Brahe Uranus velocity Venus Verrier zenith