Nautical Tables Designed for the Use of British SeamenF. & J. Rivington, 1849 - 399 pages |
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Page xi - ... converted into time, shows how long it is after 6 o'clock before the sun rises, and how long before 6h the sun sets. The longest night and shortest day, therefore, become equal respectively to the longest day and shortest night, as before found. It will be perceived from what is above shown, that when the latitude and declination are both north or both south, the sun rises before and sets after 6 o'clock ; but when one is north and the other south, the sun rises after and sets before 6. 89. We...
Page xii - Atcention for Sidereal Hours. — This table contains the difference between any interval as expressed in sidereal time, and the same interval as expressed in mean solar time. It is particularly useful in turning sidereal time into mean solar time as follows. From sidereal time, increased if necessary by 24 hours, subtract the right ascension of the sun at the preceding apparent noon. The remainder will be the interval between apparent noon and the given instant, as shown by a sidereal clock.
Page x - Rising and Setting of the Sun. — By the bearing amplitude of the sun is meant the arc of the horizon intercepted between the east point and the point where the sun rises, or between the west point and the point where it sets. It is reckoned from the east and west points towards the north or south, according as the declination is north or south.
Page ix - ... with this and the mean true zenith distance, as if it were the meridian zenith distance, find an approximate latitude. Then add together 5'314425, log cosine approximate latitude, log cosine declination, log cosec. mean true zenith distance, and log. of the mean nat versine (adding 4 to proper index). The sum, rejecting the tens from the index, will be the log. of a number of seconds, which find from the tables, and subtract them from the mean true zenith distance...
Page x - Meridional Parts.— At the Equator a degree of longitude is equal to a degree of latitude ; but as we approach the poles, while...
Page iv - ... happens to be. In this case the dip is greater than in the open sea. The table is entered with the estimated height of the eye and the estimated distance of the shore ; the correction taken out is subtractive. Table (g), p. 4. Augmentation of the Moon's Semidiameter. — The semidiameter of the moon put down in the Nautical Almanac...