A History of the Navigator's Sextant

book summary

Introduction. The Genesis of the Mariner's Angle-measuring. The Seaman's Quadrant. Mariner's Astrolabe, Nautical Ring and Semicircle. The Cross-Staff. Shadow Staffs. Early Instruments of Reflection. Improvements to Hadley's Octant. Marine Sextants in the Twentieth Century. Sextants for Coastal Navigation and Surveying. Artificial Horizons for Marine Sextants. Sextants for Air Navigation.