American Practical Navigator: An Epitome of Navigation and Nautical Astronomy |
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Page 7
... Star or Planet . Alt . upper limb . Alt . lower limb . Azimuthal angle . A a ..Alpha . BB.Beta . IT H - Gamma . ..Delta . ..Epsilon . Zeta . Eta . I К к △ 2 Degrees . Minutes of Arc . " Seconds of Arc . h Hours . m Minutes of Time . 5 ...
... Star or Planet . Alt . upper limb . Alt . lower limb . Azimuthal angle . A a ..Alpha . BB.Beta . IT H - Gamma . ..Delta . ..Epsilon . Zeta . Eta . I К к △ 2 Degrees . Minutes of Arc . " Seconds of Arc . h Hours . m Minutes of Time . 5 ...
Page 9
... stars . 4. Navigation and Nautical Astronomy have been respectively termed Geo- Navigation and Celo - Navigation , to indicate the processes upon which they depend . 5. As the method of piloting can not be employed excepting near land ...
... stars . 4. Navigation and Nautical Astronomy have been respectively termed Geo- Navigation and Celo - Navigation , to indicate the processes upon which they depend . 5. As the method of piloting can not be employed excepting near land ...
Page 19
... stars . When fitted with a telescope the pelorus may be used to take the azimuth of The standard compass is usually located in the ship in the central fore - and - aft standard compass being located , all peloruses may be oriented line ...
... stars . When fitted with a telescope the pelorus may be used to take the azimuth of The standard compass is usually located in the ship in the central fore - and - aft standard compass being located , all peloruses may be oriented line ...
Page 87
... stars . 210. THE CELESTIAL SPHERE . - An observer upon the surface of the earth appears to view the heavenly bodies as if they were situated upon the surface of a vast hollow sphere , of which his eye is the center . In reality we know ...
... stars . 210. THE CELESTIAL SPHERE . - An observer upon the surface of the earth appears to view the heavenly bodies as if they were situated upon the surface of a vast hollow sphere , of which his eye is the center . In reality we know ...
Page 93
... star ; move the index until the reflected image appears to pass if one passes on either side of the other the the direct image ; if one passes directly over the other the mirrors must be parallel ; INSTRUMENTS EMPLOYED IN NAUTICAL ...
... star ; move the index until the reflected image appears to pass if one passes on either side of the other the the direct image ; if one passes directly over the other the mirrors must be parallel ; INSTRUMENTS EMPLOYED IN NAUTICAL ...
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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.