298 GEOGRAPHY AND ASTRONOMY. At 90 degrees from N mark E and Q on each side ; then cross the axis of the world N s with the line E Q at right angles, which represents the equator. Thus E will be 90 degrees from N the north pole, 511 degrees from z the zenith, whichis the latitude, and it will be 381 degrees above H the horizonwhich is the complement of the latitude. At 23 degrees from E on each side mark the points el and w; then parallel to the equator or E Q draw the line M 23 for the tropic of cancer, and the w Vß for the tropic of Capri- corn. After that, through the centre c draw nt Vß which is the ecliptic : It cuts the equator E Q in c, and makes an angle with it of 23f degrees. From the points N s mark p and x on each side at the dis- tance of 23f degrees, p p are the poles of the ecliptic, and the line p x and x p being drawn are the two polar circles, viz. the artic and antartic. Thus analemma is completed for all general purposes or problems. The further observables in it are these, viz. M is the sun's place in the ecliptic when it enters cancer at the summer's solstice : and the arch E M iS its north declination 23f degrees. c is the sun's place in the ecliptic entering aries or libra at the equinoxes ; and then it has no declination. VS is the sun's place in the ecliptic entering Capricorn at the winter solstice ; and the arch VS Q or (which is all one) E w is its south declination 23f degrees. The line is the sun's path the longest day, or at the summer solstice ; it is at 23 at midnight ; it rises at a it is at six o'clock at 6; itis in the east azimuth at v; it is on the meri- dian at M that day, and the arch M H is its meridian altitude, viz. 62 degrees. The line E Q is the sun's path on the two equinoctialdays at aries and libra; it is at midnight at Q ; it rises at c, and it is in the same moment at the east, and six o'clock ; for on the equi- noctial days z D the azimuth of the east and west, and N s the six o'clock hour ling both meet at e in the horizon H o, which never happens any other day in the year ; then the sun goes up to E at noon ; and a H is the arch of its meridian altitude at the equinoxes, viz. 381 degrees. w VS' is the sun's path the shortest day, or at the winter solstice ; it is at midnight at VS ; it is in the east at it long be- fore it rises ; it is six o'clock at G before it rises also ; 'then at 1 it rises or gets. above the horizon ; it is noon at w, and its meri- dian altitude is w H or 15 degrees. The sun's ascensional difference (that is, its distance from six o'clock at its rising nr setting) in the summer solstice is the linen 6, and at the winter solstice'tis the line i G.
RkJQdWJsaXNoZXIy OTcyMjk=