Outlines of AstronomyLongman, green and Roberts, 1859 - 714 pages |
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Page 27
... impression respecting their places , which must be rectified by ascertaining the amount and direction of the displacement so apparently produced on cach , before we can come at a knowledge of the true directions in REFRACTION . 27.
... impression respecting their places , which must be rectified by ascertaining the amount and direction of the displacement so apparently produced on cach , before we can come at a knowledge of the true directions in REFRACTION . 27.
Page 29
... amount of atmospheric refraction , or the strict determination of the angle S A s , by which a celestial object at any assigned altitude , H A S , is raised in appearance above its true place , is , unfortunately , a very difficult ...
... amount of atmospheric refraction , or the strict determination of the angle S A s , by which a celestial object at any assigned altitude , H A S , is raised in appearance above its true place , is , unfortunately , a very difficult ...
Page 30
... amount of this diminution at different heights , is not yet fully ascertained . Moreover , the refracting power of air is perceptibly affected by its moisture ; and this , too , is not the same in every part of an aërial column ...
... amount of this diminution at different heights , is not yet fully ascertained . Moreover , the refracting power of air is perceptibly affected by its moisture ; and this , too , is not the same in every part of an aërial column ...
Page 31
... amount of refraction , for an object half- way between the zenith and horizon , or at an apparent alti- tude of 45 ° , is about 1 ' ( more exactly 57 " ) , a quantity hardly sensible to the naked eye ; but at the visible horizon it amounts ...
... amount of refraction , for an object half- way between the zenith and horizon , or at an apparent alti- tude of 45 ° , is about 1 ' ( more exactly 57 " ) , a quantity hardly sensible to the naked eye ; but at the visible horizon it amounts ...
Page 34
... difference of den- sity in the aërial strata , must also have , corresponding to it , a certain amount of refraction ; less , indeed , than what wou'd be produced by the whole atmosphere , but still often 34 OUTLINES OF ASTRONOMY .
... difference of den- sity in the aërial strata , must also have , corresponding to it , a certain amount of refraction ; less , indeed , than what wou'd be produced by the whole atmosphere , but still often 34 OUTLINES OF ASTRONOMY .
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Common terms and phrases
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 effect epoch equal equator equinoctial equinox error exact excentricity fixed globe gravity heavens heliocentric hemisphere horizon inclination increase inequality instance instrument interval 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 precisely proper motions proportion recede recess reckoned refraction remarkable render respect result revolution revolving right ascension ring 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 whole zenith