Synopsis
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. 1900 Excerpt: ...Semi-Diameter from page III. of the month in the Nautical Almanac. Take out the Equation of Time from page IT. of the Nautical Almanac. Then find the Apparent Time of the Moon's Meridian Passage or Transit at the Port in the following way: Owing to the Moon's proper motion the Time of Transit is in East Longitude, earlier, and in West Longitude later, than the Time of Transit at Greenwich; a correction for Longitude has therefore to be applied to the Greenwich Time of Transit. If you are in East Longitude find the difference between the Times of the Moon's Transit at Greenwich on the day and on the day before. If you are in West Longitude find the difference between the Times of Transit on the day and on the day after. Enter Table XVI. with this difference to the nearest minute at the top, and the Longitude to the nearest degree in the left-hand column, and take out the correction. Apply the correction to the Greenwich Time of Transit, deducting it if you are in East, and adding it if you are in West Longitude. The result is the Mean Time of Transit at the Port. To this apply the Equation of Time, and you have the Apparent Time of Transit at the Port. Enter Table XVI. with the Apparent Time of Transit in the left-hand column, and the Moon's SemiDiameter at the top, and take out the correction. Apply this correction to the Mean Time of Transit, and to the sum or remainder add the Establishment--that is the time of High Water at full and change--of the Port. The result is the time of the P.M. Tide of the given day. If you want the A.m. Tide subtract 24 minutes from the P.M. Tide. The objection to this method is that it is decidedly faulty, and may land you in an error of an hour. The most accurate plan is to make a Constant for yourself on any Standard Port a...
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