A course of practical astronomy for surveyors with the elements of geodesy

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Printed at the Daily News Office, 1883 - Geodesy - 185 pages
 

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Page 98 - Sun, the larger plane.ts and certain stars as they would appear from the centre of the Earth. When a Lunar Distance has been observed on the surface of the Earth, and reduced to the centre, by clearing it of the effects of parallax and refraction, the numbers in these pages enable us to ascertain the exact Greenwich mean time at which the objects would have the same distance. They are arranged, from west to east...
Page 142 - J of the true spherical excess, the sines of these angles will be proportional to the lengths of the opposite sides, and the triangle may therefore be calculated as if it were plane.
Page 171 - In this projection a different cone is used for each parallel of latitude. Each cone has the parallel for its base and its vertex at the point where a tangent to the earth at the given parallel of latitude intersects the earth's axis. The F1G.
Page 7 - The earth, in its travel around the sun, keeps its axis always nearly parallel to itself. The axis is inclined to the plane of the orbit at an angle of 23° 27'.
Page 166 - ... it on a plane so that the distances of places shall retain the same proportions which they have on the sphere, and geographers have accordingly had recourse to various methods of delineation, all of which have their peculiar advantages in particular cases. One method is to represent the points and lines of the sphere according to...
Page 167 - IN the projection of crystals, the eye is supposed to be at an infinite distance, so that the rays of light fall from it on the crystal in parallel lines. The plane on which the crystal is projected is termed the plant: of projection.
Page 20 - The prime vertical is the great circle which passes through the zenith and the east and west points of the horizon.
Page 61 - ... always of exactly the same length, or, in other words, if it gains or loses exactly the same amount every hour and every day. The time-pieces used in astronomical observation are the chronometer and the clock.
Page 98 - ... the centre of the Earth. When a Lunar Distance has been observed on the surface of the Earth, and reduced to the centre, by clearing it of the effects of parallax and refraction, the numbers in these pages enable us to ascertain the exact Greenwich mean time at which the objects •would have the same distance. They are arranged, from west to east, commencing each day with the object which is at the greatest distance westward of the Moon, in the precise order in which they appear in the heavens...
Page 167 - X), or else failure will occur on the surface of a cone whose axis coincides with that of the specimen. On the other hand, if the ends of the specimen are carefully lubricated to prevent the formation of the lateral restraining forces which arise in the unlubricated case, the specimen fails by "splitting" along axial planes, as seen Fig.

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