On navigation simplified - Tapa blanda

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. 1906 Excerpt: ... the twenty-four hours. You must be careful when the Declination is changing from S. to N. and N. to S. in March and September; note--Use Page 1, Nautical Almanac. f in this case when the correction is subtracted and exceeds the Declination, take the Declination from the Correction, and call the remainder the Declination of the contrary name. The following examples illustrate these rules: Example i.--May 20th, 1899, in West Longitude. Time by Chronometer 4h. 18m. P. M., corrected. The observed Meridian Altitude of the Sun's lower limb was 65 48' 58" bearing South. Index error + 1' 10"; height of the eye 14 feet. Required the Latitude. Latitude... 44 00 00 N. Note.--When the tenths are over 5 call them 1 second more. The Chronometer gives time from Greenwich Mean Noon, for which reason we use Page II of the Nautical Almanac, which gives only 2" more than Page 1, so it makes little difference which page is used. Page 1 is the same as the Abridgment used by most Ship Masters. It will be seen at a glance that this method of correcting the Declination for Meridian Altitude by Chronometer, same as a Time sight, is much more correct and less work than the usual way of using Longitude by Dead Reckoning for that purpose. Example 2.--May 3d, 1899, the Observed Meridian Altitude of the Sun's lower limb was 6o 20' 30" bearing North. Height of eye 17 feet. Longitude by Dead Reckoning 6o E. Required the Latitude. Dec. G. A. Noon, 15 41' 32".2N Cor. for Long.--2 56.3 Cor. Dec... 15 38 35.9 N H. D. Dec. 44".07 Long.6o E= X 4th 176.28=2' s6".3 S. N. Latitude... 13 49 31 S. SHORT METHOD OF WORKING ABOVE EXAMPLE. The 89 48' Method, known by all Navigators, is a constant of (12') taken from 900, instead of adding 12' to the Altitude. It does ...