Handbook of Astronomy

altitude aphelion apparent diameter apparent magnitude apparent motion ascertained astronomers atmosphere attraction axis bodies C. H. F. Peters called celestial equator celestial sphere centre change of position circle comet conjunction density determined direction discovered discovery disk disturbing diurnal diurnal motion earth ecliptic edge effect equal equinoxial points excentricity explained firmament globe greater heat heavens hemisphere Herschel horizon increase inferior conjunction inferior planet instrument interval Jupiter latitude less light longitude lunar Mädler mass matter mean distance millions of miles moon moon's move nearly nebula night object Observatory observed opposition orbit parallax passes the meridian perihelion period phenomena planet planetary Plate pole produced ratio refraction revolution revolve right angles right ascension ring rotation round the sun satellites Saturn seen sidereal solar system sphere spots stars sun's supposed surface synodic period telescope terrestrial tides tion Uranus variation velocity vertical visible visual wires zenith