Definitions and Explanations of Navigation and Nautical Astronomy: For the Use of Naval Cadets on Board H.M.S. "Britannia."

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Griffin & Company, 1887 - Nautical astronomy - 63 pages
 

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Page 5 - The axis of a circle of a sphere is the diameter of the sphere which is perpendicular to the plane of the circle. The ends of the axis are called the poles of the circle.
Page 39 - A Solar Day is the interval of time between two successive transits of the sun over the same meridian; and the hour-angle of the sun is called Solar Time.
Page 21 - POINTS, because, when the centre of the solar disk arrives at them, being then in the celestial equator, the sun will be equal times above and below the horizon (2367), and the days and nights will be equal. 2431. The vernal and autumnal equinoxes. — The equinoxial point at which the sun passes from the south to the north of the celestial equator is called the VEKNAL, and that at which it passes from the north to the south is called the AUTUMNAL, equinoxial point. The TIMES at which the centre...
Page 42 - The angle between the first and last directions of a ray which has suffered two reflexions in one plane is equal to twice the inclination of the reflecting surfaces to each other.
Page 33 - ... intercepted between the first point of Aries and the circle of declination passing through the place of the body in the celestial concave.
Page 5 - A SPHERE is a solid bounded by a surface every point of which is equally distant from a fixed point which is called the centre of the sphere.
Page 7 - ... south to north), the other as the First Point of Libra (the point on the ecliptic where the sun's declination changes from north to south). Circles of Declination. — Are great circles which pass through the poles of the heavens ; they correspond to terrestrial meridians. Parallels of Declination. — Are small circles whose planes are parallel to the plane of the equinoctial. Declination. — Is the arc of a circle of declination intercepted between the equinoctial and the place of the body....
Page 39 - A tropical year is the interval of time between two successive passages of the sun through the vernal equinoctial point.
Page 33 - The declination and right ascension of a heavenly body may be defined thus : the declination of a heavenly body is the arc of the circle of declination passing through its place in the celestial concave, intercepted between this place and the celestial equator ; the right ascension of a heavenly body is the arc of the celestial equator...
Page 5 - A sphere is a solid bounded by a surface, every point of which is equally distant from a fixed point called the centre. A Great Circle.

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