jan 1, 1461 - The quadrant is first used at sea

Description:

A quadrant is a scientific instrument most often used by sailors to measure what longitude, latitude, or time they may be at. Versions of the tool date back to the year 150, and versions of it were experimented with in Medieval Europe,.

It was not until 1461 that Diogo Gomes, a Portuguese explorer, began using the instrument at sea. Sailors began using it to find their latitude by measuring the height of Polaris in the sky, improving the ease of navigation. Later in 1618, English mathematician Edmund Gunter improved the design substantially and thus the quadrant continued to be used by sailors around the globe for centuries to come.

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