History of Astronomy |
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Page 129
... Sirius . In 1738 J. Cassini 3 showed that the former had moved five minutes of arc since Tycho Brahe fixed its position . In 1792 Piazzi noted the motion of 61 Cygni as given above . For a long time the greatest observed proper motion ...
... Sirius . In 1738 J. Cassini 3 showed that the former had moved five minutes of arc since Tycho Brahe fixed its position . In 1792 Piazzi noted the motion of 61 Cygni as given above . For a long time the greatest observed proper motion ...
Page 134
... Sirius being about half a century . Later he said : " I adhere to the conviction that Procyon and Sirius form real binary systems , consisting of a visible and an invisible star . There is no reason to suppose luminosity an essential ...
... Sirius being about half a century . Later he said : " I adhere to the conviction that Procyon and Sirius form real binary systems , consisting of a visible and an invisible star . There is no reason to suppose luminosity an essential ...
Page 135
... Sirius to be o " .38 . From this it has been calculated that the mass of Sirius equals two of our suns , and its intrinsic brightness equals twenty suns ; but the companion , having a mass equal to our sun , has only a five - hundredth ...
... Sirius to be o " .38 . From this it has been calculated that the mass of Sirius equals two of our suns , and its intrinsic brightness equals twenty suns ; but the companion , having a mass equal to our sun , has only a five - hundredth ...
Page 136
... Sirius and Procyon , leads to the inference that if ever the plane of such a binary orbit were edge - on to us there ought to be an eclipse of the luminous partner whenever the non - luminous one is interposed between us . This should ...
... Sirius and Procyon , leads to the inference that if ever the plane of such a binary orbit were edge - on to us there ought to be an eclipse of the luminous partner whenever the non - luminous one is interposed between us . This should ...
Page 144
... Sirius , Vega , Regulus , Altair . The characteristic feature of their spectra is the strength and breadth of the hydrogen lines and the extreme faintness of the metallic lines . This class of star is white to the eye , and rich in ...
... Sirius , Vega , Regulus , Altair . The characteristic feature of their spectra is the strength and breadth of the hydrogen lines and the extreme faintness of the metallic lines . This class of star is white to the eye , and rich in ...
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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 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