American Practical Navigator: An Epitome of Navigation and Nautical Astronomy |
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Page 21
... given latitude , expressed in minutes at the equator as a unit , constitutes the number of Meridional Parts corresponding to that latitude . The Table of Meridional Parts or Increased Latitudes ( Table 3 ) , computed for every minute of ...
... given latitude , expressed in minutes at the equator as a unit , constitutes the number of Meridional Parts corresponding to that latitude . The Table of Meridional Parts or Increased Latitudes ( Table 3 ) , computed for every minute of ...
Page 27
... given by the attached thermometer 74 ° ; then we have : Observed height of the mercury . Correction for temperature ( 74 ° ) ... 29.95 -0.12 Height of the mercury at standard temperature ... 29.83 56. THE ANEROID BAROMETER . - This is ...
... given by the attached thermometer 74 ° ; then we have : Observed height of the mercury . Correction for temperature ( 74 ° ) ... 29.95 -0.12 Height of the mercury at standard temperature ... 29.83 56. THE ANEROID BAROMETER . - This is ...
Page 33
... given of such points as seem to require it . 68. THE WIND . In recording the force of the wind the scale devised by the late Admiral Sir F. Beaufort is employed . According to this scale the wind varies from 0 , a calm , to 12 , a ...
... given of such points as seem to require it . 68. THE WIND . In recording the force of the wind the scale devised by the late Admiral Sir F. Beaufort is employed . According to this scale the wind varies from 0 , a calm , to 12 , a ...
Page 37
... given heading of the ship , and must be corrected for the deviation on that heading for conversion to magnetic , and for both deviation and variation for conversion to true bearings or courses . The process of applying the errors under ...
... given heading of the ship , and must be corrected for the deviation on that heading for conversion to magnetic , and for both deviation and variation for conversion to true bearings or courses . The process of applying the errors under ...
Page 40
... given stated times in advance , draw on cross - section paper a curve whose ordinates are minutes of local apparent time and whose abscissæ are degrees of magnetic azimuth , that is , true azimuth corrected for variation . Then for any ...
... given stated times in advance , draw on cross - section paper a curve whose ordinates are minutes of local apparent time and whose abscissæ are degrees of magnetic azimuth , that is , true azimuth corrected for variation . Then for any ...
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Common terms and phrases
azimuth barometer bearing celestial sphere Center chart Chro chronometer Church circle Coast Corr correction corresponding cosec course dead reckoning declination departure determined deviation Diff Difference of Latitude difference of longitude direction Dist E.
H. W.
L. W. Spg earth east equal equator EXAMPLE Extreme Flagstaff Greenwich Greenwich mean h. m.
h. m. ft Harbor Head horizon hour angle instrument intersection Island Islet light Lighthouse logarithm Long longitude lunitidal interval magnetic MARITIME POSITIONS mean sun measured meridian altitude method miles nat hav Nautical navigator Neap noon object Observatory observed altitude parallax parallel plane Port POSITIONS AND TIDAL prime vertical rhumb line right ascension Rock Sailing sextant ship ship's sidereal sight station Summit Sumner line sun's telescope theodolite TIDAL DATA tides true vertical vessel watch wind zenith distance
Popular passages
Page 257 - Each degree is divided into 60 equal parts called minutes, and each minute into 60 equal parts called seconds.
Page 26 - St.-Cu.) at the center of the group, but the thickness of the layer varies. At times the masses spread themselves out and assume the appearance of small waves or thin slightly curved plates. At the margin they form into finer flakes (resembling Ci.-Cu.) They often spread themselves out in lines in one or two directions.
Page 5 - Lines are generally marked as follows: 2 fathoms from the lead, with 2 strips of leather, 3 fathoms from the lead, with 3 strips of leather, 5 fathoms from the lead, with a white rag, 7 fathoms from the lead, with a red rag, 10 fathoms from the lead, with leather having a hole in it, 13 fathoms from the lead, same as at 3 fathoms...
Page 54 - ... the fixed arm. To plot a position, the two angles observed between the three selected objects are set on the instrument, which is then moved over the chart until the three beveled edges pass respectively and simultaneously through the three objects. The center of the instrument will then mark the ship's position, which may be pricked on the chart or marked with a pencil point through the center hole. The...
Page 142 - Having sailed from Charleston, SC, 25th November, 1837, bound for Greenock, a series of heavy gales from the westward promised a quick passage; after passing the Azores the wind prevailed from the southward, with thick weather; after passing longitude 21° W. no observation was had until near the land, but soundings were had not far, as was supposed, from the bank. The weather was now more boisterous and very thick, and the wind still southerly; arriving about midnight, 17th December, within 40 miles,...
Page 257 - THEOREM. Every section of a sphere, made by a plane, is a circle.
Page 86 - Moon, having a distance of 90° or more, are brought into contact just at the wire of the telescope which is nearest the plane of the sextant, fixing the index, and altering the position of the instrument to make the objects appear on the other wire ; if the contact still remains perfect, the axis of the telescope is in proper adjustment ; if not, it must be altered by moving the two screws which fasten, to the up-and-down piece, the collar into which the telescope screws. This adjustment is not...
Page 97 - Sun, and other fundamental astronomical data for equi-distant intervals of Greenwich mean time. Part II, Ephemeris for the Meridian of Washington, gives the ephemerides of the fixed stars, sun, moon, and major planets for transit over the meridian of the old Naval Observatory, Washington.
Page 95 - Time, which is perfectly equable in its increase, is measured by the motion of this mean sun. The clocks in ordinary use and the chronometers used by navigators are regulated to mean solar time. True, or Apparent Solar Time is measured by the motion of the real sun. The difference between apparent and mean time is called the Equation of Time.