Rudimentary Astronomy

61 Cygni aberration accuracy aphelion apogee appear apse axis body calculated catalogue centre comet computed correction curve describe diameter direction discovery disk disturbing force ditto earth earth's orbit earth's surface ecliptic effect elements elliptic orbit epoch equal equator equatorial equinox error evection excentricity fixed geocentric gravitation Greenwich heavens Hence Herschel horizon inclination increase inequalities instrument Jupiter Kepler's known latitude light line of apsides longitude lunar orbit magnitude mass mean anomaly mean distance mean motion measured meridian moon moon's mural circle nearly node nutation object observations Observatory Otto Struve parallax perigee perihelion period planet planetary polar distances pole position precession proper motions quadrature quantity radius vector reader refraction revolution revolve right angles right ascensions rotation round the sun satellites sidereal sidereal period solar orbit space stars sun's supposed syzygy telescope tion transit Treatise true anomaly true longitude velocity Venus zenith distances