A History of Nautical Astronomy

accuracy apparent altitude astrolabe astronomical navigation azimuth calculated celestial body celestial horizon celestial meridian celestial pole celestial sphere centre chronometer computed correction cosine cross-staff described difference double-altitude problem Earth eclipses equal altitude equation equinoctial error ex-meridian finding latitude finding longitude fixed stars formula given Greenwich haversines heavenly body Hipparchus hour angle instrument invention known latitude and longitude logarithms longitude at sea longitude by chronometer lunar distance Maskelyne mathematical means measuring meridian altitude meridian passage method for finding minutes of arc Moon Moon's motion Nautical Almanac nautical astronomy Nautical Magazine noon observed object observer's parallax plane polar distance Pole Star position line practical published PZX triangle quadrant refraction Right Ascension rule satellites seamen sextant ship ship's position sight sin² solution spherical triangle Sumner's method Sun's declination tion trigonometry tude values vane vers vertical zenith distance