The Elements of the Theory of Astronomy |
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Common terms and phrases
aberration altitude angular apparent diameter apparent place argument of latitude ascension and declination azimuth called clock conjunction cos² described determined direction disk diurnal circle Earth Earth's center Earth's surface east ecliptic equal equator equinox error fixed stars formulæ geocentric greatest heavenly body heavens heliocentric Hence horizon hour angle inclination inferior planet intersection interval Jupiter known latitude and longitude length line joining lunar lunar eclipse mean distance meridian zenith distance motion nearly node observed parallax parallel passing perigee perihelion perpendicular plane point of Aries pole position precession radius vector refraction right ascension rotation round satellite seen semi-diameter shadow sidereal sidereal day sidereal period sin² solar eclipse solstice star's Sun and Moon Sun's declination supposed telescope tion transit triangle true true anomaly values velocity Venus vertical visible zenith distance
Popular passages
Page 55 - The radii vectores describe areas in one plane proportional to the time. (2) The orbits are ellipses having the Sun in one of their foci. (3) The squares of the periodic times are proportional to the cubes of the mean distances from the Sun. The
Page 116 - divided into 24 equal parts or hours, each hour into 60 minutes, and each minute into 60 seconds. The sidereal day is the interval between two successive transits of the true first point of Aries
Page 16 - Latitude. The Longitude of a star is the arc of the ecliptic intercepted between the first point of Aries and a secondary to the ecliptic passing through the star;
Page 264 - if the mean angular velocity of the first satellite be added to twice that of the third, the sum will equal three times that of the second.
Page 54 - The times of these phenomena observed under any meridian, when compared with that computed for Greenwich in the Nautical Almanac, give the longitude of the observer within a few miles.
Page 332 - As the Sun only shines on the dial during half the day, if the dial fronts the east, it points out the time from sun-rise to noon, or if the dial fronts the west, from noon to night.
Page 293 - be seven eclipses; five of the Sun and two of the Moon, or four of the Sun and three of the Moon, in the
Page 137 - of finite extent, limited by the weight of ultimate atoms of definite magnitude, no longer divisible by the repulsion of their parts;
Page 59 - may happen at the same node after an interval of eight years, but if it does not happen then, it cannot take place again at the same node