Outlines of astronomy

amount angle angular appear apsides ascertained astronomical attraction axis bright calculation celestial circle comet curve described diameter difference direction disc distance disturbed body disturbing force diurnal diurnal motion double stars earth ecliptic Edition effect epoch equal equator equinoctial equinox error exact excentricity fixed globe gravity heavens heliocentric hemisphere horizon inclination inequality instance instrument interval Julian period Jupiter latitude latter less light longitude lunar magnitude mass mean measure meridian moon moon's motion nearly nebula node normal force nutation object observed orbit parallax parallel perigee perihelion period perturbations phænomena planet planetary pole portion position precession proper motions proportion recede reckoned refraction remarkable respect result revolution revolving right ascension rotation round satellites Saturn seen sidereal sidereal day situation solar sphere spherical stars station sun's suppose surface syzygies tangential force telescope tion Uranus variation velocity visible vols whole zenith