Mathematics and Society - OS X Lion Server

ASTRONOMYGLOSSARYtan~zodtangent. Two circles in the sameplane are tangent if they touch inexactly one point.transit. An instrument used by surveyorsto measure the angular separationbetween two distant objects.zenith. The point on the celestialsphere directly above the observer.zodiac. A band on the celestial sphere,centered on the ecliptic, that containstwelve constellations.(transversal.other lines.A line that crosseS twotriangulation. A method of measuringdistances indirectly that is basedupon similar triangles.vernal equinox. One of the two intersectionsof the celestial equatorand the ecliptic. The sun is at thispoint on the first day of spring.north celestial poleeclipticvernal equinox __~__~celestial equatorvertical angles. When two lines meetangles are formed. Angles I and 3 arevertical angles; so are angles 2 and 4.14 23waning. The moon is waning when thelighted portion that we see is becomingsmaller; when the moon is changingfrom a full moon to a new moon.watt.A unit of power.waxing. The moon is waxing when thelighted portion that we see is becominglarger; when the moon is changingfrom a new moon to a full moon.124