Tables Requisite to be Used with The Nautical Ephemeris,: For Finding the Latitude and Longitude at Sea

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T. Bensley, sold by James Payne and John Mackinlay., 1802 - Logarithms - 206 pages
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Page 64 - ... in the Ephemeris; the remainder will be the proportional logarithm of a portion of time to be. added to the hour answering to the nearest distance, to obtain the approximate Greenwich mean time corresponding to the given distance.
Page 48 - ... centre. RULE. With the apparent time from noon, enter Table XXIII. and from the column of rising take out the logarithm corresponding, to which add the log. co-sine of the latitude, and the log. co-sine of the sun's declination ; their sum, rejecting 20 in the index, will be the logarithm of a natural number, which being subtracted from the natural co-sine of the sum of the declination and latitude, when they...
Page 5 - Almanac forNoon atGREENwicH, toany other Time under that Meridian or to Noon under any other Meridian. Add aft. N. Sub. b.ef. N. Sub. aft. N. Add bef. N. HM 7-4 HM
Page 37 - XXIII., and, from the column of log. rising, take out the logarithm corresponding, from which logarithm subtract the log. ratio ; the remainder will be the logarithm of a natural number, which, being found in Table...
Page 15 - SuQ ; or Star; an additional dark Glafs, lighter than the common ones, to take off the Glare of the Moon's Light in obferving her...
Page 49 - Add the Difference of the two Numbers taken out of this Table, if the Apparent Argument.
Page 31 - ... time. The difference between these times will be the time from noon when the greater altitude was taken. With this time enter Table XXIII., and, from the column of log.
Page 169 - For reducing the fun's right afcenfion in time, as given in the Nautical Almanack for noon at Greenwich, to any other time under that meridian, or to noon under any other meridian. We are here...
Page 45 - ... confequently, if the obfervation be made in the forenoon, the time, thus found, muft be taken from 24 hours, and the remainder will be the apparent time from the noon of the preceding day. Example. On the 5th of March 1780, in the afternoon, in latitude 16 24' north, and longitude 138" eaft, the altitude of the fun's lower limb was obferved to be 47 8
Page 29 - Then, if the zenith diftance and declination be both north or both fouth, add them together ; but if one be north and the other fouth, fubtracT; the lefs from the greater, and the fum or difference will be the latitude, of the fame name with the greater.

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