Navigation and Nautical Astronomy |
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NAVIGATION & NAUTICAL ASTRONOM Charles 1846 Belknap,J. H. C. (John Huntington Crane) Coffin No preview available - 2016 |
Navigation and Nautical Astronomy John Huntington Crane Coffin,Charles Belknap No preview available - 2016 |
Common terms and phrases
affect Almanac altitude angle apparent astronomical azimuth bearing body Bowd called centre chart Chro chronometer circle computed contains convenient correction corresponding course curve declination departure determined Diff difference direction distance earth east equal equator error EXAMPLES expressed formula given gives greater Greenwich height horizon hour-angle instant interpolation interval June known latitude less Long longitude mean mean sun measured meridian method middle minutes moon nearest nearly noted object observed obtained parallax parallel pass plane pole position practice PROB PROBLEM quantities radius reduce refraction regarded represent result right ascension Sailing Sept ship side sidereal Solution star subtract sufficiently surface Table taken tion transit triangle true tude vertical zenith
Popular passages
Page 98 - A cos 6 = cos a cos c + sin a sin c cos B cos c = cos a cos 6 + sin a sin 6 cos C Law of Cosines for Angles cos A = — cos B...
Page 50 - ... mean sun" which moves in a uniform rate along the equator. This is called mean solar time. The difference between mean and apparent time is called the equation of time. To convert apparent time into mean time, take from the Nautical Almanac the equation of time and add it or subtract it according to the direction given at the column.
Page 72 - Almanac the two distances between which the true distance falls; take out the nearer of these, the hours of Greenwich time over it, and the PL of Diff. between them. Find the difference between the true distance and the distance taken Jrom the Almanac; and from the proportional logarithm of this difference, as found in the Navigator, subtract the PL of Diff.
Page 100 - ... or if the bearing at this time is interpolated for from previous and subsequent bearings per compass, the error of the compass can be found. It has already been shown that compass error is the difference between the true and compass bearings of a heavenly body at the same instant, and is marked E. when the true bearing is to the right of the compass bearing, W. when the true bearing is to the left of the compass bearing.
Page 50 - ... uniform, and this for two reasons: 1st. The sun does not move in the equator, but in the ecliptic, so that, even were the sun's motion in the ecliptic uniform, its equal changes of longitude would not produce equal changes of right ascension; 2d. The sun's motion in the ecliptic is not uniform. To obtain a uniform measure of time depending on the sun's motion, the following method is adopted. A fictitious sun, which we shall call the...