A Treatise on Nautical Astronomy for the Use of Students

A Treatise on Nautical Astronomy for the Use of Students

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1886 edition. Excerpt: ...June at 4h. 30m. p.m. it was found slow 2m. 49s. What is its daily rate? March 23, 8h. 30m. a.m. slow 5m. 13s. June 18, 4 30 p.m. slow 2 49 Gain in 87 days.." Daily rate Second Method, by equal altitudes of the same star on the same side of the meridian on different days.--We have already shown, p. 36, that the mean solar day is longer than the sidereal day by 3m. 55'91s. of mean solar time; that is, the same star returns to the meridian 3m. 55'91s. earlier each day than on the preceding one, and will, therefore, at the same place, return to any one altitude on the same side of the meridian earlier each day by that interval. Hence the difference between 3m. 55-91s. and the interval shown by a chronometer when a star has equal altitudes on the same side of the meridian on two consecutive days is the rate. In practice it is preferable to allow several days to elapse between the observations, and to select a star whose altitude is as great as possible and is changing quickly, and should therefore lie near the prime vertical. If the interval by the chronometer be less than 3m. 55'91s. j'er day, it is gaining; but if the interval by chronometer be greater than that, it is losing. Ex. 309. On August 6th, at lOh. 7m. 46s., the altitude of Arcturus by an artificial horizon west of the meridian was 46 31'. On August 29th, at 8h 34m. 50'5s. by the same chronometer, the star had the same altitude west with the same sextant. Required the rate of the chronometer. August 6, chronometer showed lOh. 7m. 46s. August 29, 8 34 50'5 Diff. in time for eq. alts. in 23 days = 1 32 55-5 1 day = 4 2-41 but true, = 3 55'91 Hence rate = 6'5 losing. If the error be required it may be calculated as by the first method....show more

Product details

  • Paperback | 96 pages
  • 189 x 246 x 5mm | 186g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236623207
  • 9781236623201