The Cambridge Course of Elementary Physics: Astronomy. Part third

angle angular distance appear ascertained astronomers atmosphere attraction axis ball called celestial pole centre circle comets computed constellation crater curve dark density describe diameter Dominical Letter double stars earth eclipse equal equator equinox faculæ Figure fixed star Give an account gravity acts heavenly bodies heavens Hence Herschel horizon inches inclined inferior conjunction inferior planet interval Jupiter known length light luminous lunar magnitude Mars mean distance measured Mercury meridian miles moon moon's mountain moving naked eye nebula observed opposite orbit oscillation parallax particles passes path pendulum penumbra polar distance position proper motion pull relative distance revolution revolve ring rotation satellites Saturn seen shadow side sidereal period spots square straight line sun's disc superior planet suppose surface synodical period tance telescope tion transits of Venus triangle twilight umbra Uranus velocity Venus vibrations visible weight zenith zodiacal light