Sextants at Greenwich —— A Catalogue of the Mariner's Quadrants, Mariner's Astrolabes Cross-staffs, Backstaffs, Octants, Sextants, Quintants, Reflecting Circles and Artificial Horizons in the National Maritime Museum, Greenwich.

----- 格林威治的六分仪

ISBN: 9780199532544 出版年：2009 页码：353 Morzer Bruyns, W F J Dunn, Richard Oxford University Press

This book describes the history and development of navigating instruments. Before satellites these were used to measure the altitude of the sun and stars above the horizon, to determine the ship's position at sea. The book also contains a catalogue of 347 mariner's astrolabes, cross-staffs, backstaffs, and octants, sextants and artificial horizons.