Octant by John Greenwood 1793

octant

Octant by Greenwood of Providence. Mahogany frame; ivory scale and inlay; brass on part of the arm and fittings. Horizon mirror cracked, one set of shades loose, no handle. Inlayed plaque on crosspiece engraved, "Made * By * Greenwood * Providence * 1793*/ I*Smellage*". Octant (or Hadley's Quadrant) was the first of the commonly used reflecting instruments for measuring the angular heights of sun and stars above the horizon. These angular measurements were required for determining latitude and longitude in celestial navigation.