Jean-Baptiste Morin

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Jean-Baptiste Morin

1583-1656

French astronomer who proposed a method for determining terrestrial longitude at sea based on observations of the Moon's motion relative to the stars. Morin's method required nautical instruments of much greater precision than existed, better mathematical solutions for spherical triangles, and refined lunar tables. Though unable to provide a practical proposal for implementation of his method, Morin did make important contributions to instrumental technique by introducing the telescopic sights and Vernier micrometers for angle measurements.