The Elements of Astronomy: Designed for the Use of Students in the University |
Other editions - View all
Common terms and phrases
aberration aphelion apogee apparent place appear astronomers atmosphere axis called Cassini centre circle clock comet computed conjunction consequently dark declination described determined diameter difference disc discovered diurnal motion draw earth eclipse emersion equal equinox excentricity fixed stars Flamstead gives greater Halley happen heavenly bodies heavens hence Trig Herschel horary motion horizon horizontal parallax hour angle inclination inferior conjunction interval Jupiter latitude libration light lunar magnitude Mars mean anomaly mean distance mean motion Mercury meridian altitude moon moon's orbit nearly node observed opposition orbit parallax parallel perihelion perpendicular phænomena Phil planet pole proper motion radius refraction revolve right ascension ring rotation satellite Saturn seen semidiameter shadow sidereal sine solar spectator spots sun and moon sun's supposed surface synodic revolution telescope tion Trans transit triangle true anomaly true longitude true place tude umbra Venus visible zenith
Popular passages
Page 151 - Object would not be the same when the Eye is at Rest, as when it is moving in any other Direction, than that of the Line passing through the Eye and Object; and that, when the Eye is moving in different Directions, the apparent Place of the Object would be different.
Page 141 - ... the squares of the periodic times are as the cubes of the distances from the common centre, the centripetal forces will be inversely as the squares of the distances.
Page 6 - The Latitude of a star is its angular distance from the ecliptic measured on a circle of latitude.
Page 180 - ... and therefore there is a greater probability of seeing a lunar than a solar eclipse. Since the moon is as long above the horizon as below, every spectator may expect to see half the number of lunar eclipses which happen.
Page 217 - Observer' at a salary of 100£ per annum, his duty being 'forthwith to apply himself with the most exact care and diligence to the rectifying the tables of the motions of the heavens and the places of the fixed stars, so as to find out the so much desired longitude of places for the perfecting the art of navigation.
Page 118 - ... it had a degree of brightness about as strong as that with which such a coal would be seen to glow in faint daylight.
Page 204 - He further observes, that there are some additional circumstances in the appearance of extended clusters and nebula-, that very much favour the idea of a power lodged in the brightest part. For, although the form of them be not globular, it is plainly to be seen that there is a tendency towards sphericity, by the swell of the dimensions...
Page 205 - ... in diameter. The star is perfectly in the centre, and the atmosphere is so diluted, faint, and equal throughout, that there can be no surmise of its consisting of stars ; nor can there be a doubt of the evident connection between the atmosphere and the star.
Page 40 - The Equation of Time is computed by taking the Difference of the Sun's true right Ascension and his mean Longitude corrected by the Equation of the Equinoxes in right Ascension, and turning it into Time at the Rate of 1
Page 72 - That the planets all move in elliptic orbits, of which the sun occupies one of the foci. 3. That the squares of the times of the revolutions of the planets are as the cubes of their mean distances from the sun.