History of Astronomy |
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Page 87
... spectrum . To over- come the spherical aberration James Gregory , 1 of Aberdeen and Edinburgh , in 1663 , in his Optica Promota , proposed a reflecting speculum of parabolic form . But it was Newton , about 1666 , who first made a ...
... spectrum . To over- come the spherical aberration James Gregory , 1 of Aberdeen and Edinburgh , in 1663 , in his Optica Promota , proposed a reflecting speculum of parabolic form . But it was Newton , about 1666 , who first made a ...
Page 90
... spectrum . These are the Frauenhofer lines , some of which he named by the letters of the alphabet . The D line is a very marked one in the yellow . These dark lines in the solar spectrum had already been observed by Wollaston.1 On ...
... spectrum . These are the Frauenhofer lines , some of which he named by the letters of the alphabet . The D line is a very marked one in the yellow . These dark lines in the solar spectrum had already been observed by Wollaston.1 On ...
Page 91
... spectrum showed the D line black ; or the vapour of sodium absorbs the same light that it radiates . This proved to him the existence of sodium in the sun's atmosphere.1 Iron , calcium , and other elements were soon detected in the same ...
... spectrum showed the D line black ; or the vapour of sodium absorbs the same light that it radiates . This proved to him the existence of sodium in the sun's atmosphere.1 Iron , calcium , and other elements were soon detected in the same ...
Page 92
... spectrum of a star alongside a spectrum of hydrogen , we may see all the lines , and be sure that there is hydrogen in the star ; yet the lines in the star - spectrum may be all slightly displaced to one side of the lines of the ...
... spectrum of a star alongside a spectrum of hydrogen , we may see all the lines , and be sure that there is hydrogen in the star ; yet the lines in the star - spectrum may be all slightly displaced to one side of the lines of the ...
Page 102
... spectrum instead of calcium K - for example , the hydrogen line H ( ) - we obtain two photographs , one showing the ... spectrum . But Rowland , of Baltimore , after having perfected the art of making true gratings with equidistant lines ...
... spectrum instead of calcium K - for example , the hydrogen line H ( ) - we obtain two photographs , one showing the ... spectrum . But Rowland , of Baltimore , after having perfected the art of making true gratings with equidistant lines ...
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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 nebulę 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