Outlines of Astronomy

altitude amount angle angular appear apsides arise ascertained astronomical atmosphere axis body calculation cause celestial circle clock coincidence comet degree described deviation diameter difference direction disc disturbing force diurnal motion double stars earth earth's surface ecliptic effect epoch equal equator equinoctial equinox error evident exact excentricity fixed globe heavens heliocentric hemisphere horizon hour angle instance instrument interval Jupiter latitude latter less light longitude lunar magnitude mass mean measure meridian moon moon's nearly nebula node normal force nutation object observed orbit parallax parallel passing perigee perihelion period perpendicular phænomena plane pole portion position precession precisely proper motion proportion rays recede reckoned refraction render respect result revolution revolving right ascension rotation round satellites seen sidereal sidereal day situation solar spectator sphere spherical stars station sun's suppose syzygies tangential telescope tion Uranus velocity vernal equinox vertical visible whole zenith