A Manual of Spherical and Practical Astronomy: Spherical astronomy

accuracy approximate ascension and declination assumed axis azimuth BESSEL celestial celestial sphere centre Chro chronometer clock correction co-ordinates computed constant Corr corresponding cos² d₁ deduced denote determine difference of longitude earth eclipse employed Ephemeris equations of condition equinox expressed formula geocentric given gives Greenwich Greenwich mean h₁ hence horizon hour angle instant instrument interpolation interval latitude logarithms mean meridian meridian altitude method METHOD.-BY moon nearly noon nutation obtain P₁ parallax plane pole position precession precision prime vertical probable error proper motion quantity radius reduced refraction result right ascension semidiameter sextant sidereal sin² solar sphere star star's substitute sun's supposed T₁ term tion transit triangle true vertical circle whence zenith distance