^ CELESTIAL LATITUDE AND LONGITUDE. 



) 



is obi3erved by the most inattentive spectator ; but the ^ 

 knowledge of the latter must be the resuh of patient ob- . 

 servation. i 



The other primary planets, when seen from the sun, do 

 not describe exactly the same circle among the stars, that 1 

 the earth docs ; but are sometimes on one side of the ecliptic \ 

 and sometimes on the other. But none of them, except i 

 Juno, Pallas, and Ceres, are ever farther distant from the ] 

 ecliptic than eight degrees. So that within a zone or belt \ 

 of sixteen degrees, that is, eight degrees on each side of the i 

 ecliptic, the planets, except those just named, are always to I 

 be found. This zone, or broad belt, is called the Zodiac, s 

 The ecliptic then is an imaginary circle in the heavens pass- i 

 ing through the middle of the zodiac, and situated in the 1 

 plane of the earth's orbit. A plane is an even level surface, j 

 If you suppose a smooth thin solid plane cutting the sun J 

 through the centre, extending out as far as the fixed stars, | 

 and terminating in a circle which passes through the middle * 

 of the zodiac ; in this plane the earth would move in its re- ^ 

 volution round the sun ; it is therefore called the plane of 5 

 the earth's orbit. The points, where the orbit of any hea- 

 venly body cuts the plane of the ecliptic, are called the nodes ] 

 of that body. The point, where the body passes from the ' 

 north side of the plane of the ecliptic to the south, is called ] 

 its descending node ; where it passes from the south to the \ 

 north, its ascending node. J 



The ecliptic, as well as every other circle, great or small, 5 

 is divided into three hundred and sixty degrees ; but it has j 

 also another division into twelve signs, of thirty degrees each, \ 

 called the twelve signs of the zodiac. These signs derive 

 their names from clusters of stars, or constellations, which, as \ 

 the ancients imagined, resembled certain animals. They are f, 

 most commonly represented by characters, and the names -, 

 given them should be made familiar ; for the sun, as he ap- j 

 pears to move round in the ecliptic, seems to enter these clus- J 

 ters of stars, and is therefore said to be in this or that sign, j 



If the axis of the earth be supposed to extend both ways J 

 to the starry heavens, its places or points among the stars | 

 are the celestial poles, one north and the other south, direct- | 

 ly over or beyond the poles of the earth of the same name. ^ 

 If the plane of the earth's equator were extended every way | 

 to the starry heavens, the circle it would make among the J 



