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affirmative altitude apparent diameter ARGUMENT ascension and declination astronomical axis body called celestial sphere centre circle comet computed consequently corrected corresponding Cotang Diff difference disc diurnal motion dominical letter earth eclipse equal equator equatorial parallax Evection fixed star formulŠ full moon geocentric greatest Greenwich heliocentric Hence horizon horizontal parallax hour angle hourly motion hourly variation interval Jupiter logarithm longitude and latitude mean anomaly mean longitude Mercury meridian motion in longitude Nautical Almanac nearly node nutation obliquity observed obtained parallax parallel perigee perihelion period perpendicular planet pole position quantities radius vector refraction retrograde motion revolution right ascension satellites semidiameter shadow sidereal sine solar subtract sun's longitude sun's mean surface tang tangent telescope tion triangle true true longitude Venus vernal equinox visible zenith distance
Page 17 - The azimuth of a body is the arc of the horizon intercepted between the north or south point of the horizon, and a vertical circle passing through the body.
Page 79 - The squares of the periods of revolution of any two planets are proportional to the cubes of their mean distances from the sun.
Page 75 - Year, and consists of 365 days, в hours, 9 minutes, and 9. 6 seconds, which is invariable. The Tropical Year is the interval between two consecutive returns of the Sun to the Vernal Equinox.
Page 112 - Hence, t — 0/,nn — -, -r\ 8600 — (m — m') is given in the Nautical Almanac for every day in the year, It may easily be found for any other meridian by proportion.
Page 11 - Uranus, and Neptune. Five of these planets, namely — Mercury, Venus, Mars, Jupiter, and Saturn are visible to the naked eye, and were known to the ancients. Uranus, the Asteroids, and Neptune have been discovered in modern times by the aid of the telescope ; and there may be others yet undiscovered.
Page 100 - That node where the planet passes from the south to the north side of the ecliptic, is called the ascending node ; and the other is the descending node.
Page 16 - The declination is reckoned north or south, according as the body is on the north or south side of the equator.
Page 107 - These phases prove conclusively that the moon shines by light borrowed from the sun. The interval from one new moon to the next new moon is called a lunation, or lunar month. It is evidently the same as a synodical revolution of the moon.