That is the reason we are using the word Variation exclusively, as Bowditch does, for clarity and lack of confusion. “Declination” (magnetic affects of the world) should not be confused with “Deviation” (magnetic effects of the ship). NOTE: Variation is the same as Declination See NOAA Geomagnetism and Wikipedia The direction north as indicated by a magnetic compass the reference direction for measurement of compass directions. Called MAGNETIC DEVIATION when a distinction is needed to prevent possible ambiguity. Deviation of a magnetic compass after adjustment or compensation is RESIDUAL DEVIATION. Semicircular deviation changes sign (E or W) approximately each 180° change of heading quadrantal deviation changes sign approximately each 90° change of heading constant deviation is the same on any heading. Deviation is caused by disturbing magnetic influences in the immediate vicinity of the compass. The angle between the magnetic meridian and the axis of a compass card, expressed in degrees east or west to indicate the direction in which the northern end of the compass card is offset from magnetic north. The direction indicated by the north seeking pole of a freely suspended magnetic needle, influenced only by the earth’s magnetic field. Called MAGNETIC VARIATION when a distinction is needed to prevent possible ambiguity. The angle between magnetic and grid meridians is called GRID MAGNETIC ANGLE, GRID VARIATION, or GRIVATION. The angle between the magnetic and geographic meridians at any place, expressed in degrees and minutes east or west to indicate the direction of magnetic north from true north. True North, The direction of the north geographical pole the reference direction for measurement of true directions. True north is the direction of the north geographical pole magnetic north the direction north as determined by the earth’s magnetic compass grid north an arbitrary reference direction used with grid navigation. The primary reference direction relative to the earth the direction indicated by 000° in any system other than relative. A vector quantity equal to speed in a given direction. Such a quantity may be represented geometrically by an arrow of length proportional to its magnitude, pointing in the given direction. Any quantity, such as a force, velocity, or acceleration, which has both magnitude and direction, as opposed to a SCALAR which has magnitude only.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |