Example image of eyePlorer eyePlorer map for 'Sextant': Navigation Sextant (astronomical) Astronomical object Horizon Measuring instrument Nautical chart Position line Latitude Sun Celestial navigation Greek language Latin Octant (instrument) Quadrant (instrument) Isaac Newton Reflecting instrument John Hadley Philadelphia Thomas Godfrey (inventor) Backstaff Alidade Mariner's astrolabe Celestial Silvering Attitude indicator Monocular Degree (angle) Minute of arc Vernier scale Nautical mile Weatherproof Invar Aircraft Parallel (geometry) Plane (geometry) Telescope Collimated light Nathaniel Bowditch Astrodome (aviation) Bris sextant Celestial observation Seal of San Francisco, California 1731 in science Position circle Stadimeter Dividing engine French ship Astrolabe (1811) Henry Wilberforce-Clarke Macrometer Pioneer Instrument Company