ISBN: 9781231008638

RareBooksClub. Paperback. New. This item is printed on demand. Paperback. 30 pages. Dimensions: 9.7in. x 7.4in. x 0.1in.This historic book may have numerous typos and missing text. Purc… Mehr…

RareBooksClub. Paperback. New. This item is printed on demand. Paperback. 30 pages. Dimensions: 9.7in. x 7.4in. x 0.1in.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. 1895 Excerpt: . . . be in doubt as to whether the declination is north or south. It is obvious that it is important for the navigator to know the rate at which the declination changes. This is found in the column of the N. A. (symbol for Nautical Almanac) adjoining the declination. The first thing to do is to multiply it by the number of hours before or after Greenwich noon as shown by the chronometer, for the declination is given for noon. Secondly, if the time shown is after noon and the declination is increasing, add the ascertained variation. If the declination is decreasing, subtract the variation. If the time is before noon and the declination is increasing, subtract the variation, because the declination will, of course, be larger at noon than at any previous hour. If the declination is decreasing, add the variation. The result obtained from any of these processes is called the corrected declination. The corrected declination is always employed in figuring out the results of an observation. APPARENT AND MEAN TIME--THE EQUATION Apparent time is that shown by the sun. Mean time is that shown by the clock. The equation of time is the difference between them. The earth revolves on its axis once in 24 hours, and theoretically the sun crosses the meridian of any given place at precisely 12 oclock each day, and it is then noon. As a matter of fact this is not so. The earth does not revolve at a uniform rate of speed, and consequently sometimes the sun is a little ahead of time and again it is behind. Now you cannot manufacture a clock which will run that way. Its hours must all be of exactly the same length, and it must make noon at precisely 12 oclock every day. Hence we distinguish clock time from sun time by calling the former mean (or average) time and the latter apparen. . . This item ships from La Vergne,TN., RareBooksClub<

2012, ISBN: 9781231008638

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 illustra… Mehr…

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. 1895 Excerpt: ...be in doubt as to whether the declination is north or south. It is obvious that it is important for the navigator to know the rate at which the declination changes. This is found in the column of the N. A. (symbol for Nautical Almanac) adjoining the declination. The first thing to do is to multiply it by the number of hours before or after Greenwich noon as shown by the chronometer, for the declination is given for noon. Secondly, if the time shown is after noon and the declination is increasing, add the ascertained variation. If the declination is decreasing, subtract the variation. If the time is before noon and the declination is increasing, subtract the variation, because the declination will, of course, be larger at noon than at any previous hour. If the declination is decreasing, add the variation. The result obtained from any of these processes is called the corrected declination. The corrected declination is always employed in figuring out the results of an observation. APPARENT AND MEAN TIME--THE EQUATION Apparent time is that shown by the sun. Mean time is that shown by the clock. The equation of time is the difference between them. The earth revolves on its axis once in 24 hours, and theoretically the sun crosses the meridian of any given place at precisely 12 o'clock each day, and it is then noon. As a matter of fact this is not so. The earth does not revolve at a uniform rate of speed, and consequently sometimes the sun is a little ahead of time and again it is behind. Now you cannot manufacture a clock which will run that way. Its hours must all be of exactly the same length, and it must make noon at precisely 12 o'clock every day. Hence we distinguish clock time from sun time by calling the former mean (or average) time and the latter apparen... Weight:0.16 lbs, RareBooksClub.com, 5/8/2012 0:00:00<