New American Practical NavigatorU.S. Government Printing Office, 1880 |
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Αποτελέσματα 1 - 5 από τα 22.
Σελίδα 4
... adjustments of a transit instrument Variation of the compass . .... To calculate the true azimuth ... Having the true and magnetic amplitude or azimuth , to find the variation ..... Methods of surveying a small bank or shoal where great ...
... adjustments of a transit instrument Variation of the compass . .... To calculate the true azimuth ... Having the true and magnetic amplitude or azimuth , to find the variation ..... Methods of surveying a small bank or shoal where great ...
Σελίδα 129
... adjustment may be made by the sun , moon , or a star , by holding the quadrant in a vertical position , and observing if the object seen by reflection appears to the right or left of the object seen direct , and moving the screws , as ...
... adjustment may be made by the sun , moon , or a star , by holding the quadrant in a vertical position , and observing if the object seen by reflection appears to the right or left of the object seen direct , and moving the screws , as ...
Σελίδα 130
adjustment is complete ; if not , they must be made to coincide by means of the adjusting lever . The horizon may be used for this purpose in the following manner : — Hold the plane of the instrument vertical ; look through the lower ...
adjustment is complete ; if not , they must be made to coincide by means of the adjusting lever . The horizon may be used for this purpose in the following manner : — Hold the plane of the instrument vertical ; look through the lower ...
Σελίδα 131
... adjusting and observing . Various remedies have been proposed for these defects , but none have vet Deen generally adopted . The back observation of the altitude of any object , is useful only when there is not an open horizon for the ...
... adjusting and observing . Various remedies have been proposed for these defects , but none have vet Deen generally adopted . The back observation of the altitude of any object , is useful only when there is not an open horizon for the ...
Σελίδα 134
... adjustment ; if the coincidence of the horizons is not perfect , the adjustment must be repeated till it is so ; but as it is difficult to obtain a perfect coincidence by this means , the horizons may be brought to coincide by turning ...
... adjustment ; if the coincidence of the horizons is not perfect , the adjustment must be repeated till it is so ; but as it is difficult to obtain a perfect coincidence by this means , the horizons may be brought to coincide by turning ...
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Άλλες εκδόσεις - Προβολή όλων
Συχνά εμφανιζόμενοι όροι και φράσεις
angle apparent altitude azimuth bearing calculated Cape centre chord chronometer circle column compass Corr corresponding Cosec courses sailed degrees diameter diff difference of latitude difference of longitude Dist draw east equal equator error EXAMPLE extent will reach feet find the course find the difference given Greenwich Half-sum horizon glass horizontal parallax hour angle hypotenuse instrument latitude and departure Latitude Sailing line of numbers line of sines logarithm lower limb lunitidal interval mean meridian altitude method middle latitude miles moon moon's multiplied Nautical Almanac nearly noon object observed altitude parallel Parallel Sailing perpendicular Plane Sailing points polar distance quadrant radius 90 refraction right ascension screw sea account secant semidiameter sextant ship side sine course star subtracted sun's declination Suppose telescope transit triangle true altitude true distance true longitude variation wires
Δημοφιλή αποσπάσματα
Σελίδα 11 - The angle in a semicircle is a right angle ; the angle in a segment greater than a semicircle is less than a right angle ; and the angle in a segment less than a semicircle is greater than a right angle.
Σελίδα 15 - In any plane triangle, as the sum of the sides about the vertical angle is to their difference, so is the tangent of half the sum of the angles at the base to the tangent of half their difference.
Σελίδα 15 - In any plane triangle, the sum of any two sides is to their difference as the tangent of half the sum of the opposite angles is to the tangent of half their difference. By Theorem II. we have a : b : : sin. A : sin. B.
Σελίδα 6 - A plane rectilineal angle is the inclination of two straight lines to one another, which meet together, but are not in the same straight line.
Σελίδα 254 - Emersion (Em.) the instant of its reappearance at coming out of the shadow. They generally happen when the Satellite is apparently at some distance from the body of Jupiter, except near the opposition of Jupiter to the Sun, when the eclipse takes place near to the body of the planet.
Σελίδα 7 - In a right triangle, the side opposite the right angle is called the hypotenuse, and the other two sides the legs.
Σελίδα 233 - ... distance, to obtain the approximate Greenwich mean time corresponding to the given distance. If the distance between the Moon and a Star increased or decreased uniformly, the Greenwich...
Σελίδα 126 - ... to the depth of 80 or 100 fathoms ; then heave the log, and the number of knots run out in half a minute will be the miles the current sets per hour, and the bearing of the log will show the set of it. There is a very remarkable current, called the GULF STREAM, which sets in a north-east direction along the coast of America, from Cape Florida towards the Isle of Sables...
Σελίδα 148 - ... placed by the maker equidistant from each other and parallel to the middle one — therefore, when the middle one is adjusted, the others are so too ; he also places the two transverse wires at right angles to the vertical middle wire. These adjustments are always performed by the maker, and but little liable to derangement. When, however, they happen to get out of order, and the observer wishes to correct them, it is done by loosening the screws which hold the eye-end of the telescope in its...
Σελίδα 136 - ... 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 very liable to be deranged.