The Nautical Almanac and Astronomical Ephemeris for the Year 1867

The Nautical Almanac and Astronomical Ephemeris for the Year 1867

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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. 1863 edition. Excerpt: ...mean of the second differences is l"-1 and i of this, which is the greatest effect, is only o"-14. A similar operation performed on the parallaxes will show the error that would arise on the supposition of uniform or equal first differences, to be five-tenths of a second. Page IV. of each Month. The Moon's I.ongitude and I.atitude at mean noon and midnight indicate the position of the Moon at these respective times, referred to the Ecliptic and the true equinox, as it would be seen from the centre of the Earth. They are the results deduced immediately from the lunar tables, and are the foundation of all subsequent calculations in which the Moon is concerned. These quantities are now of little use to the seaman, as the position of the Moon, with respect to the Equator, is given for every hour in the succeeding pages; but the Moon's Longitude is involved in the formulfe for nutation, and is therefore necessaryfor its determination. In finding the Moon's Longitude and Latitude for any other times than those of mean noon and midnight, it is necessary to apply the equation of second, and sometimes even of third and fourth differences, on account of the irregular variation of her motion. The Moon's Age at mean noon is the mean time elapsed since the Moon's ecliptic conjunction with the Sun, or since the Sun and Moon had the same Longitude. The numbers in this column represent her age at Greenwich, and are expressed in days, and decimal parts of a day. The Moon's Meridian Passage.--This column contains the Greenwich mean astronomical time to the nearest tenth of a minute, at which the Moon's centre is on be obtained from an observed meridian altitude of the Moon; also, in conjunction with a Table of semidiurnal Arcs, to determine...
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Product details

  • Paperback | 26 pages
  • 189 x 246 x 1mm | 68g
  • United States
  • English
  • black & white illustrations
  • 1236832191
  • 9781236832191