Practical and Spherical Astronomy: For the Use Chiefly of Students in the Universities

aberration altitude amount angle apparent applied approximately assumed astronomical axis azimuth body calculated called centre circle colatitude collimation computed considered correction corresponding declination deduced describe determined difference direction distance Draw earth easily ecliptic effect equal equation equatorial equinox error example expressed fixed formula geocentric give given Greenwich Hence horizontal hour-angle inclination increase interval known latitude length light longitude mean solar measured meridian method moon moon's motion moving nearly necessary object obliquity Observatory observed obtain orbit parallax passing perpendicular planet polar distance pole position preceding precession produced quantity radius reading referred refraction represent right ascension seen side sidereal sin z star sun's supposed surface tables taken telescope tion transit true vertical wires zenith distance zenith-distance