The Nautical Almanac and the Astronomical Ephemeris for the Year 1848

The Nautical Almanac and the Astronomical Ephemeris for the Year 1848

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1844 edition. Excerpt: ...time, diminished by 12h, leaves January ld 15h 35m, for the corresponding astronomical time. To each month there are devoted twenty-two pages, distinguished by the Roman numerals I. to XXII. For convenience of interpolation, the quantities that follow next in order of succession have been added at the bottom of each page. Thus the quantities opposite to February 1 will be found inserted also opposite to January 32, the number of the days in each month having been intentionally increased for such purpose. Page I. of each Month. The contents of this page are adapted to Apparent Noon, or the instant when the Sun's centre is on the meridian of Greenwich. The Sun's Right Ascension, here given, is affected with Aberration, and reckoned from the true Equinox; it is therefore the Sidereal Time at Apparent Noon, or the time which ought to be shown by a Sidereal Clock, at that instant. The Sun's Apparent Declination is the angular distance of the Sun from the Equator, measured on the meridian. The columns entitled " Diff. for 1 hour" are intended to facilitate the reduction of the quantities from Apparent Noon to any other time. The values of these quantities for any proposed mean time will, however, be more accurately ascertained by means of the numbers on page II. from which, indeed, they have been derived. The Sidereal Time of the Sun's Semidiameter passing the Meridian is useful for reducing a transit observation of either limb of the Sun, when one only has been observed, to the transit of the centre. The Equation of Time is the difference between Apparent and Mean Time, and therefore serves for the conversion of either time into the other. The numbers here given, show, for Greenwich Apparent Noon, the distance of the mean Sun more

Product details

  • Paperback | 36 pages
  • 189 x 246 x 2mm | 82g
  • United States
  • English
  • black & white illustrations
  • 1236776690
  • 9781236776693