 | Henry Raper - Nautical astronomy - 1840 - 700 pages
...difference, or the combined effect of parallax and refraction, is called the Correction of Altitude. 334. The SEMI-DIAMETER of a celestial body is half the...angle subtended by the diameter of the visible disc. It is evident that the semi-diameter will be greater as the body is nearer, and smaller as it is further... | |
 | Janet Taylor - Nautical astronomy - 1851 - 674 pages
...the apparent altitude, but as seen from the centre the true altitude. The semidiameter of an object is half the angle subtended by the diameter of the visible disc. Augmentation. Since the moon is nearer to an observer on the earth, when she is in the zenith than... | |
 | Henry Raper - Nautical astronomy - 1882 - 952 pages
...quantities is the diff. between the true and apparent altitudes. This difference, or the combined effect of parallax and refraction, is called the Correction...from S to D and F; the half of this angle is DSC or CSF, and is called the semi-diameter. It is evident that the semi-diameter will be greater as the body... | |
 | John Bradley Harbord - Naval art and science - 1883 - 472 pages
...fipi-, which we find in Aemz'sphere, ftemicycle, etc. Semidiameter. — The semidiameter of a heavenly body is half the angle subtended by the diameter of the visible disc at the eye of the observer. For the same body the semidiameter varies with the distance ; thus the... | |
 | Nathaniel Bowditch - Nautical astronomy - 1888 - 704 pages
...being the same as was found by the table. SEMI-DIAMETER. Art. 235. The semi-diameter of a heavenly body is half the angle subtended by the diameter of the visible disc at the eye of the observer. For the same body the semi-diameter varies with the distance ; thus, the... | |
 | American School (Chicago, Ill.) - Engineering - 1903 - 390 pages
...Fig. 10. parallax an additive correction, which is the angle BSO, and is given in Table 16, Bowditch. Semidiameter of a celestial body is half the angle subtended by the body's diameter. This is an additive correction if the lower limb is used, and gives the altitude of... | |
 | Royal Geographical Society (Great Britain) - Scientific expeditions - 1906 - 514 pages
...par., is too great for any other latitude. The reduction is given in Table XVIII. The Semi- Diameter of a celestial body is half the angle subtended by the diameter of the visible disc. It is evident that the semi-diameter will be greater as the body is nearer, and smaller as it is farther... | |
 | Electrical engineering - 1906 - 680 pages
...Fig. 19. parallax an additive correction, which is the angle BSO, and is given in Table 16, Bowditch. Semidiameter of a celestial body is half the angle subtended by the body's diameter. This is an ( additive correction if the lower limb is used, and gives the altitude... | |
 | Nathaniel Bowditch - Nautical astronomy - 1906 - 670 pages
...in entering Table 24 for parallax and refraction. SEMIDIAMETEB. 3O7. Tho bemidiameter of a heavenly body is half the angle subtended by the diameter of the visible disk at the eye of the observer. For the same body the semidiameter varies with the distance; thus,... | |
 | Henry Raper - Nautical astronomy - 1908 - 1018 pages
...quantities is the diff. between the true and apparent altitudes. This difference, or the combined effect of parallax and refraction, is called the Correction...from S to D and F ; the half of this angle is DSC or CSF, and is called the semi-diameter. It is evident that the semi-diameter will be greater as the body... | |
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Since the apparent altitude is too great on account of refraction, and too small on account of parallax, the diff. between these quantities is the diff. between the true and apparent altitudes. This difference, or the combined effect of parallax and refraction,... 
