Astronomy |
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altitude amount angle angular distance apparent astronomers average axis binary binary stars bodies celestial equator celestial pole celestial sphere clusters comet Consequently constellation craters crosses the meridian declination density determined diameter direction diurnal motions double star earth earth's atmosphere eccentricity equal equatorial equinox eyepiece fact focal plane galactic galaxy gravity horizon interval Jupiter kilometers known latitude laws of motion length Lick Observatory light light-years luminosity lunar eclipse magnitude Mars mass mean solar measured Mercury meteorites meteors miles Milky moon Mount Wilson Observatory move nearly nebulae number of stars object oblate observer orbit parallax passes period phenomena photograph planetary planetoids planets position probably radiation rays refraction relative respect revolution revolve right ascension rotation satellites Saturn sidereal solar eclipses solar system spectral classes spectroscopic spectrum spherical sun's Suppose surface synodic month telescope temperature theory tion velocity Venus visible Yerkes Observatory zenith