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aberration altitude angle annual motion aphelion apogee apparent latitude apparent place Astronomers axis beginning body calculated CASSINI circle clock comet computed conjunction consequently correction declination described determined diameter difference digits eclipsed diurnal motion earth eclipse elongation equal equinox error excentricity fixed stars FLAMSTEAD geocentric given gives greater greatest equation Greenwich HALLEY heliocentric hence horary motion horizon horizontal parallax hour inclination interval Jupiter Jupiter's latitude and longitude libration logarithm lunar MASKELYNE mean anomaly mean distance mean longitude mean motion mean place Mercury method moon nearly node observations opposition orbit parallax parallel passed the meridian perihelion perpendicular planet pole radius refraction Retrograde revolution right ascension ring satellite Saturn semid semidiameter shadow sidereal sine star's subtract sun's supposed Tables telescope tion transit triangle true anomaly true longitude true place velocity Venus zenith distance
Page 499 - 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 291 - ... 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 374 - But more lunar, than solar eclipses are seen at any given place, because a lunar eclipse is visible to a whole hemisphere at once ; whereas a solar eclipse is visible only to a part, and therefore there is a greater probability of seeing a lunar than a solar eclipse.
Page 43 - 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 335 - If the plane of the moon's orbit coincided with the plane of the ecliptic, there would be an eclipse at every...
Page 416 - Comets, being impell'd towards the Sun by a centripetal Force, would descend as from Spaces infinitely distant; and, by their so falling, acquire such a Velocity, as that they may again fly off into the remotest Parts of the Universe, moving upwards with a perpetual Tendency, so as never to return again to the Sun.
Page 206 - ... as strong as that with which such a coal would be seen to glow in faint daylight. The adjacent parts of the volcanic mountain seemed faintly illuminated by the eruption. A similar eruption appeared on May 4, 1783.
Page 335 - An eclipse is a partial, or total privation of the light of the sun or moon. An eclipse of the sun is caused by the interposition of the moon between the earth and the sun, and consequently must happen when the inoon is in conjunction with the sun, or at the new moon.
Page 304 - At last I conjectured that all the phenomena, hitherto mentioned, proceeded from the progressive motion of light and the earth's annual motion in its orbit. For I perceived that, if light was propagated in time, the apparent place of a fixed 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...