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18 Right Ascension Antares a Aquilæ Apparent Declination Apparent Right Ascension Aquilæ Fomalhaut Aquilæ SUN Arietis Aldebaran Arietis SATURN Aldebaran ASCENSION AND DECLINATION astronomical beginning change of declination column Day of Month Decl declination indicates difference Direction of Object Eclipse ends Equation equinox Fomalhaut a Pegasi Frid FRIDAY given GREENWICH MEAN GREENWICH MEAN NOON Hour hourly change IIIh indicates that north JUPITER Antares Fomalhaut JUPITER Antares SUN latitude longitude LUNAR DISTANCES Meridian Passage Midnight Minute MONDAY Moon MOON'S RIGHT ASCENSION Name and Direction north declinations NOTE observation P. L. of Diff Pegasi a Arietis Pegasi SUN Pollux Regulus reduced Regulus Spica JUPITER SATURN a Arietis SATURN Aldebaran Pollux Semidiameter sidereal Spica JUPITER Antares Subtracted SUN Antares SUN Spica JUPITER SUN'S SUNDAY Table Thur THURSDAY true Tues TUESDAY VENUS Spica JUPITER WEDNESDAY XVIIIh XXIh
Page 259 - Solar time is that used for all the purposes of ordinary life, and is measured by the daily motion of the sun. A Solar Day is the interval of time between two successive transits of the sun over the same meridian; and the hour-angle of the sun is called Solar Time.
Page 268 - In the case of total and annular eclipses, a rough estimate of the magnitude of the eclipse may be obtained from the position of the place relatively to the central line and to the limit. On the central line, the eclipse is annular or total, while on the limit, the limb of the moon only grazes that of the sun. More Accurate Computations.
Page 265 - Greenwich mean time, beginning at noon; the dates are therefore astronomical. All the distances that can be observed on the same day, are grouped together under that date; and the columns are read from left to right, across both pages of the same opening. The letter W. or E. is affixed to the name of the sun, planet or star, to indicate that it is on the west, or east side of the moon.
Page 227 - The sign + prefixed to the hourly change of declination indicates that north declinations are increasing or south declinations are decreasing. The sign — indicates that north declinations are decreasing or south declinations increasing. 226 GREENWICH MEAN TIME. MAY. JUNE. Month. •я Apparent Right Ascension. Var.
Page 260 - The sidereal hours are counted from 0 to 24, commencing with the instant of the passage of the true vernal equinox over the upper meridian, and ending with its return to the same meridian. About March '21st of each year the sidereal clock agrees with the mean time, or ordinary clock, and the former gains on the latter about 3"1 56...
Page 1 - ... to the chronologists, to the 747th, and, according to the astronomers, to the 746th year, before the birth of Christ...
Page 95 - The semidiameter for mean noon may be assumed the same as that for apparent noon. The sign -+- prefixed to the hourly change of declination indicates that north declinations are increasing; the si^n — indicates that north declinations arc decreasing.
Page 266 - By a table of common logarithms, or a table of logarithms of small arcs, the reduction of the Greenwich time would be found thus: — From Ephemeris . . . . . . . PL 0.3276 Diff. of distances, 8' 35" = 515
Page 265 - Time, given at the end of the volume for 1871, saves the operation of reducing degrees (or hours) and minutes to seconds, and the reverse. As the PL of Diff. in the Ephemeris varies, the Greenwich time found by the methods just described may not be sufficiently exact. To correct it for such variation, or second difference, take the difference between the PL of Diff! used and the one which follows it in the Ephemeris, (or, more strictly, half the difference of the preceding and following ones).
Page 259 - Moon, the obliquity of the ecliptic, the nutation, the positions of 383 standard stars, the ephemeris for the meridian of Washington, etc. TIME. Astronomers make use of three different kinds of time, namely: First, true or apparent solar time; second, mean solar time; third, sidereal time. True or Apparent Solar Time. — This species of time is called indiscriminately either true solar time or apparent solar time, and is measured by the motion of the true Sun; the length of the...