American Practical Navigator: An Epitome of Navigation and Nautical Astronomy |
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... object by two bear- ings , degrees Time , speed , and distance tables ( not in these editions – refer to 1988 edition , Table 13 , page 140 ) Logarithms of numbers Logarithms of trigonometric func- tions , degrees Logarithmic and ...
... object by two bear- ings , degrees Time , speed , and distance tables ( not in these editions – refer to 1988 edition , Table 13 , page 140 ) Logarithms of numbers Logarithms of trigonometric func- tions , degrees Logarithmic and ...
Page 9
... objects thereon . It comprises ( a ) Piloting , in which the position is ascertained from visible objects upon the earth , or from soundings of the depth of the sea , and ( b ) Dead Reckoning , in which the position at any moment is ...
... objects thereon . It comprises ( a ) Piloting , in which the position is ascertained from visible objects upon the earth , or from soundings of the depth of the sea , and ( b ) Dead Reckoning , in which the position at any moment is ...
Page 11
... object be measured , the approximate rate of sailing will be given . The log - chip is the float , the log - line is the measure of the distance , and the log - glass defines the interval of time . The log - chip is a thin wooden ...
... object be measured , the approximate rate of sailing will be given . The log - chip is the float , the log - line is the measure of the distance , and the log - glass defines the interval of time . The log - chip is a thin wooden ...
Page 12
... objects available for fixing the position of the vessel and the course and speed are influenced by a tidal or other current , this log is sometimes used , its advantage being that the lead marks a sta- tionary point to which motion may ...
... objects available for fixing the position of the vessel and the course and speed are influenced by a tidal or other current , this log is sometimes used , its advantage being that the lead marks a sta- tionary point to which motion may ...
Page 18
... objects . The instrument varies widely in its different forms ; the essential features which all share consist in ( a ) a pair of sight vanes , or equivalent device , at the extremities of the diameter of a circle that revolves ...
... objects . The instrument varies widely in its different forms ; the essential features which all share consist in ( a ) a pair of sight vanes , or equivalent device , at the extremities of the diameter of a circle that revolves ...
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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.