A Treatise on Spherical Astronomy

aberration apparent approximately assume axis becomes body calculation celestial sphere centre circle constant coordinates correction corresponding cos² cosec course declination determined difference direction distance earth ecliptic effect equal equation error expression follows formula fundamental given gives graduated Greenwich Hence horizon hour angle inclination increase indicated interval known latitude length longitude Math mean measured meridian method moon moon's motion move node nole noon observer obtain orbit origin parallax parallel passes period perpendicular planet pole position precession projection Prove quantities R₁ radius reading refraction regard respectively result right ascension rotation round seen side sidereal sin² solar spherical star substitution sun's supposed surface taken transit triangle Trip true whence zenith distance zero