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
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.
Sextants at Greenwich consists of two main sections: The introductory chapters and the catalogue of navigating instruments of the National Maritime Museum. The first section gives a general overview of the history of celestial navigation with an emphasis on the instruments that were developed and used for that purpose, between about 1450 and the 1970s. The instruments in the catalogue form the main thread in these chapters. The catalogue consists of 347 entries of instruments for celestial navigation, the octants, sextants and related instruments preserved in the National Maritime Museum. Each entry includes the place of the object's origin, its maker, the object's date, inscriptions (by the maker and/or relating to an owner), the graduated scale, the instrument's dimensions and a general description that includes details such as used materials and detached parts. Finally the object's provenance (previous owners and/or users) and references to literature on its history and handling are given.
An Introduction to the History of Celestial Navigation; The History and Development of Instruments for Measuring Altitude at Sea, before the Octant; The Invention of the Octant, its Development and Diffusion; The Sextant and Further Improvements in the Eighteenth Century; Innovations and Production in the Nineteenth and Twentieth Centuries; Collecting and Interpreting Navigational Instruments at the National Maritime Museum; The Catalogue; Appendices