Elementary astronomy; a beginner's text-book (1899)
Holden, Edward Singleton, 1846-1914 · New York, H. Holt and company · leaf 46
BF which is called agreat circle of the sphere. A great circle of the sphere isone cut from the surface by a plane passing through thecentre of the sphere. Suppose a right line POP perpen-dicular to this plane. The points P and P in which itintersects the surface of the sphere are every where 90°… … Fig. 8.—The Sphere ; its Great Circles ; their Poles. I. The angle POQ between the poles is equal to the in-clination of the planes to each other. II. The arc BD which measures the greatest distancebetween the two circles is equal to the arc PQ whichmeasures the angle POQ. III. The points E and F,…
Astronomy
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