History of Astronomy |
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Page 87
... spectrum . To over- come the spherical aberration James Gregory , ' 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 , ' 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 . ' 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 . ' 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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accepted accurate ancient appear astronomers attraction bodies bright calculations called catalogue cause centre century Chinese circle comet compared complete Copernicus determined diameter direction discovered discovery distance earth eclipse effect elements enabled epicycles equal error explain fact fixed follow force four Galileo gave give given gravitation heavens held Herschel increased interesting Jupiter Kepler knowledge known later LIBRARIES light lunar Mars mass mathematical mean measured method miles moon moon's motion move Newton noticed object observations Observatory opposition orbit original parallax pass period photographic physical planet planetary pole position predicted progress proper motion proved records researches revolve ring rotation round Royal satellites seems seen showed SIGILLUM solar system spectroscope spectrum stars studied sun's supposed surface tables telescope theory tion trace true Tycho Brahe UNIVERSITY VERITAS