Outlines of astronomy |
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Page 19
... the visible horizon appears depressed below the direction of a spirit - level- that is called See these instruments described in Chap . III . m . the dip of the horizon . It is a correction C 2 THE HORIZON AND ITS DIP . 19.
... the visible horizon appears depressed below the direction of a spirit - level- that is called See these instruments described in Chap . III . m . the dip of the horizon . It is a correction C 2 THE HORIZON AND ITS DIP . 19.
Page 29
... described by the refracted ray is concave downwards , the tangent As will lie above A S , the unrefracted ray : consequently the object S will appear more elevated above the horizon A H , when seen through the refracting atmosphere ...
... described by the refracted ray is concave downwards , the tangent As will lie above A S , the unrefracted ray : consequently the object S will appear more elevated above the horizon A H , when seen through the refracting atmosphere ...
Page 34
... described by travellers under the name of the " After - glow , " would seem to arise from this cause . ( 46. ) From the explanation we have given , in arts . 39 and 40 , of the nature of atmospheric refraction , and the mode in which it ...
... described by travellers under the name of the " After - glow , " would seem to arise from this cause . ( 46. ) From the explanation we have given , in arts . 39 and 40 , of the nature of atmospheric refraction , and the mode in which it ...
Page 42
... described are not of the same magnitude for all the stars ; and that those described by different stars differ greatly in respect of the parts of them which lie above the horizon . Some , which lie towards the quarter of the horizon ...
... described are not of the same magnitude for all the stars ; and that those described by different stars differ greatly in respect of the parts of them which lie above the horizon . Some , which lie towards the quarter of the horizon ...
Page 43
... described by those which rise exactly in the east point . Carrying his eye farther northwards , he will notice , at length , stars which , in their diurnal motion , just graze the horizon at its north point , or only dip below it for a ...
... described by those which rise exactly in the east point . Carrying his eye farther northwards , he will notice , at length , stars which , in their diurnal motion , just graze the horizon at its north point , or only dip below it for a ...
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amount angle angular appear apsides ascertained astronomical attraction axis bright calculation celestial circle comet curve described diameter difference direction disc distance disturbed body disturbing force diurnal diurnal motion double stars earth ecliptic Edition effect epoch equal equator equinoctial equinox error exact excentricity fixed globe gravity heavens heliocentric hemisphere horizon inclination inequality instance instrument interval Julian period Jupiter latitude latter less light longitude lunar magnitude mass mean measure meridian moon moon's motion nearly nebula node normal force nutation object observed orbit parallax parallel perigee perihelion period perturbations phænomena planet planetary pole portion position precession proper motions proportion recede reckoned refraction remarkable respect result revolution revolving right ascension rotation round satellites Saturn seen sidereal sidereal day situation solar sphere spherical stars station sun's suppose surface syzygies tangential force telescope tion Uranus variation velocity visible vols whole zenith