The American Ephemeris and Nautical AlmanacU.S. Government Printing Office, 1911 |
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Common terms and phrases
1.0 Mean Solar 9 ΙΟ Apparent Declination APPARENT PLACES Apparent Right Ascen Aquarii Arietis ASCENSION AND DECLINATION Auriga Besselian Boötis Camelop Cancri Cephei Ceti CIRCUMPOLAR STARS Cygni D'ya Day of Month Decl Declina Mean Right Diff Draconis Dw a Dy eclipse Ephemeris Eridani Geminorum GREENWICH MEAN NOON Groombridge h m h m Heliocentric Herculis Horizontal Parallax Hour Angle II.I II.N July June Latitude Leonis Libræ longitude Majoris Mean Place Mean Right Declina Mean Solar Date Merid meridian Moon MOON'S RIGHT ASCENSION North Observatory Octantis Ophiuchi Parallax Pegasi Piscium PLACES OF CIRCUMPOLAR Right Declina Mean Sagittarii satellite Scorpii Semidi Semidiameter Sept Sidereal sion Sun's Tauri Thur tion N tion Solar Ascen TRANSIT AT WASHINGTON Tues UPPER TRANSIT Ursa Minoris Virginis WASHINGTON MEAN ΙΟ Ο.ΟΙ
Popular passages
Page xiii - Period, which corresponds, according to the chronologists, to the 747th, and, according to the astronomers, to the 746th year, before the birth of Christ ;
Page 708 - Passage shows the hour, minute and tenth of that passage of the planet over the meridian of Greenwich which occurs next after the noon of the date. The right ascension and declination of a planet are required whenever it is observed for time, latitude or azimuth. The mode of reducing the ephemeris positions of planets to other instants of Greenwich mean time is the same as that given for the Sun on pages 554 — 555.
Page 702 - The civil day begins at midnight and comprises 24 hours, the hours being counted from 0 to 12 in two scries, the first marked am running from midnight to noon and the second marked pm running from noon to midnight. The astronomical day begins at noon on the civil day of the same date, the...
Page 706 - Page III contains, for Greenwich mean noon of each day, The Sun's True Longitude and Latitude, and the Logarithm of the Radius Vector of the Earth. The longitudes of the Sun are the true geometric longitudes, not corrected for aberration.
Page 701 - Therefore clocks and chronometers can not be regulated to apparent solar time, which may, however, be determined by observations of the Sun when visible. Mean Solar Time is measured by the motion of a fictitious body called the mean Sun, which is supposed to move uniformly in the celestial equator, completing the circuit in one tropical year. Since mean solar tune is uniform and regular in its passage, clocks and watches may be regulated to it, and those in ordinary use are usually so regulated.
Page iii - Greenwich, gives the ephemerides of the sun and moon, the geocentric and heliocentric positions of the major planets, the sun's coordinates, and other fundamental astronomical data for equidistant intervals of Greenwich mean time ; Part II, Ephemeris for the meridian of Washington gives the ephemerides of the fixed stars, sun, moon, and major planets for transit over the meridian of Washington ; and Part III, Phenomena, contains predictions of phenomena to be observed with data for their computation.
Page 715 - Computations.—A more accurate determination of the phases, as visible at any point of the Earth's surface, may be obtained from the Besselian elements which are given for every ten minutes of Greenwich mean time. Their geometric signification is as follows:— Let us imagine a plane passing through the center of the Earth, perpendicular to the right line joining the...
Page 562 - Greenwich mean time of beginning and ending at any place may be found with an uncertainty which will vary from three or four minutes for a high Sun to fifteen or twenty minutes when the Sun is near the horizon.
Page xvi - Conjunction, or having the same Longitude or Right Ascension. D Quadrature, or differing ±90° in Longitude or Right Ascension.
Page 706 - A column of hourly differences enables the computer to obtain the sun's longitude for any hour from noon. The hourly differences of the logarithm of the radius vector are likewise given. The latitude is referred to the ecliptic of the date. The last column on page III contains...