astronomy test study material

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celestial sphere- the apparent dome or sphere of sky surrounding the earth.

horizon- the line formed in the distance where the earth and sky appear to meet, 0 degree altitude

zenith- the highest point in the celestial sphere, the point in the sky directly overhead, 90 degree altitude.

nadir- the place on the celestial sphere exactly opposite the zenith, the lowest point, directly toward the center of the earth

celestial meridian- the imaginary line from the north point on the horizon through the zenith to the south point on the horizon

north and south geographic poles- imaginary points on the earth's surface that mark the intersection of the axis of rotation, about which the earth appears to spin

north celestial pole- the point on the celestial sphere directly above the earth's north geographic pole, all stars appear to revolve around this point

circumpolar stars- stars that appears to revolve around the north celestial pole without setting below the horizon

equator- imaginary line that circles the earth exactly half way between the north and south poles

celestial equator- the celestial sphere has a celestial equator (an extension of earth's equator) which is the imaginary line formed by the projection of the earth's equator on the celestial sphere

ecliptic- as seen from the earth, it is the imaginary line formed by the apparent path of the sun through the background of stars during the course of the year

zodiac- means zone of animals, refers to the 12 traditional constellations along the plane of the ecliptic through which the sun appears to pass during the year, the constellation that the sun appears to be in at the time of your birth is your sign for astrological purposes

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