Pugsley's New Guide to the United States Local Inspectors Examination of Masters and Mates of Ocean-Going Steam and Sailing Ships, Containing All Useful Information and Explaining and Many Other Useful Calculations Not Included in the Examination (Paperback)

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. 1917 Excerpt: ...star's hour angle from the star's right ascension, and if the right ascension is too small, add twenty-four hours to it, and the result will be the right ascension of meridian. From the right ascension of meridian, subtract the corrected sidereal time or right ascension of mean sun; but if the right ascension of meridian is too small, add twenty-four hours to it, and the result will be the local astronomical mean time at ship. The difference between the local astronomical mean time and Greenwich astronomical mean time will be the longitude in time, and this is turned into degrees, etc. It is not probable that the examiners will give the applicant this problem, either to work or write about. However, they can if they wish to. Latitude by Meridian Altitude of a Fixed Star. The star's meridian altitude is observed. Correct it for instrumental'error, dip and refraction which will give the true altitude. Subtract the true altitude from ninety degrees and the result will be the zenith distance and is named contrary to the star's bearing. If the zenith distance and declination from pages 248, 249 or 250, of the Nautical Almanac are both north or both south, add them together and their sum will be the latitude. If one is north and the other south, their difference will be the latitude and takes the name of the greater. Among navigators it is customary to compute the time the desired star will pass the meridian and its approximate meridian altitude. To find the time a star will pass the meridian, subtract the sun's right ascension, from page I of the Nautical Almanac, from the star's right ascension, and the result will be the local apparent time of the star's meridian passage. If the local mean time of the star's meridian passage is required, use the sidereal time ...