American Practical Navigator: An Epitome of Navigation and Nautical Astronomy |
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Page 22
... Coast lines and other positions are plotted on the chart by their latitude and longitude . A chart may be transferred from any other projection to that of Mercator by drawing a system of corresponding parallels of latitude and meridians ...
... Coast lines and other positions are plotted on the chart by their latitude and longitude . A chart may be transferred from any other projection to that of Mercator by drawing a system of corresponding parallels of latitude and meridians ...
Page 37
... coast of Australia . When due to the last - named cause , it may be a source of great danger to the mariner , but , fortunately , the number of localities subject to local attraction is limited . The amount of this error can seldom be ...
... coast of Australia . When due to the last - named cause , it may be a source of great danger to the mariner , but , fortunately , the number of localities subject to local attraction is limited . The amount of this error can seldom be ...
Page 64
... coast , and sufficiently distant from each other to give a fair - sized horizontal angle ; the latter requires a well - charted object of known height . 155. In figure 21 , let AMB be a portion of the coast along which a vessel is ...
... coast , and sufficiently distant from each other to give a fair - sized horizontal angle ; the latter requires a well - charted object of known height . 155. In figure 21 , let AMB be a portion of the coast along which a vessel is ...
Page 68
... coast upon the open ocean , while bays , bights , inlets , and large rivers operate to augment the tidal effects , and it is in the vicinity of these that one finds the highest tides and strongest currents . The navigator need there ...
... coast upon the open ocean , while bays , bights , inlets , and large rivers operate to augment the tidal effects , and it is in the vicinity of these that one finds the highest tides and strongest currents . The navigator need there ...
Page 70
... Coast piloting involves the same principles and requires that the ship's positions be continuously determined or ... coast in a fog and , unless soundings can be got that will reasonably assure the navigator of his distance from the ...
... Coast piloting involves the same principles and requires that the ship's positions be continuously determined or ... coast in a fog and , unless soundings can be got that will reasonably assure the navigator of his distance from the ...
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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.