 | Henry Raper - Nautical astronomy - 1840 - 700 pages
...body from the zenith, and is the complement of the altitude to 90°, as Z A. 327. The altitude of a body, as seen from the surface of the earth, is called...altitude. A ray of light, proceeding from the body to the eye, in traversing the earth's atmosphere, which is heavier, or denser, as it is nearer the... | |
 | Janet Taylor - Nautical astronomy - 1851 - 674 pages
...circle. Parallels of altitude are circles parallel to the horizon. The altitude of a celestial object as seen from the surface of the earth, is called the apparent altitude, but as seen from the centre the true altitude. The semidiameter of an object is half the angle subtended... | |
 | John Craig (F.G.S.) - 1859 - 1116 pages
...body. PARALLAX, par'al-laks, з. (paraUaxû, Gr.) In Astronomy, the difference between the position of a celestial body as seen from the surface of the earth, and that in which it would be seen if the observer were placed at the centre of the earth. In Practical... | |
 | Thomas Liddell Ainsley - Merchant marine - 1875 - 416 pages
...body from tho horizon, as observed with tho sextant or other instrument. 31. Apparent Altitude is tho altitude of a celestial body as seen from the surface of the earth ; or, the observed altitude corrected for index error and dip. 33. True altitude is the altitude of... | |
 | Thomas Liddell Ainsley - 1880 - 482 pages
...heavenly body from the horizon, as observed witn the sextant or other instrument. 31. Apparent Altitude is the altitude of a celestial body as seen from the surface of the earth ; or, the observed altitude corrected for index error and dip. 33. True Altitude is the altitude of... | |
 | Henry Raper - Nautical astronomy - 1882 - 952 pages
...is the measure. The zenith distance is, therefore, the complement of the altitude to 90°, as Z A. 432. The altitude of a celestial body, as seen from...altitude ; as seen from the centre, the true altitude. A lay of light, proceeding from the body, when not in the zenith, to the eye, in traversing the earth's... | |
 | Royal Geographical Society (Great Britain) - Scientific expeditions - 1906 - 514 pages
...is the measure. The zenith distance is, therefore, the complement of the altitude to 90°, as Z A. The altitude of a celestial body, as seen from the...is nearer the surface, is bent more and more as it approaches the earth, towards the perpendicular direction ; and as the spectator sees any object, not... | |
 | Henry Raper - Nautical astronomy - 1908 - 1018 pages
...is the measure. The zenith distance is, therefore, the complement of the altitude to 90°, as Z A. 432. The altitude of a celestial body, as seen from...proceeding from the body, when not in the zenith, So the eye, in traversing the earth's atmosphere, which is heavier, or denser, as it is nearer the... | |
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... of Altitude are circles parallel to the horizon. 431. ZENITH DISTANCE is the arc included between the zenith and the celestial body, or the angular distance of a body from the zenith of which that arc is the measure. The zenith distance is, therefore,... 