The stars and arrangement of the heavens have always fascinated humankind. Using the sun and stars, ancient people could navigate their journeys accurately. Both land and sea could be traversed using this navigation method. The navigation method of the stars and sun evolved, requiring both mathematical equations and constant measurement. One of the various instruments designed for this purpose was the sextant. Using a sextant, navigators could use their angle in relation to either the sun or the North Star, Polaris, to determine their exact latitude. With a sextant's measurements, navigators could pinpoint their exact latitude using the sun and North Star, Polaris, as anchoring points. Utilizing a sextant, the sun, and North Star, Polaris, navigators were able to determine their exact latitude on the earth's surface.
Civilizations with strong mathematician and astronomer populations were the first to promote the use of sextants. Usually, astronomers and mathematicians were the same person. Though Arabs, Byzantines, and early Chinese had their own versions of the sextant, the Arabs were the very first, using their thumb and finger. With a square shape and cord through the middle, the kamal was a sextant later developed by the Arabs. An important piece of the kamal, the cord allowed for the precise definition of angles. The kamal traveled through the ancient world via the Silk Road, traveling as far east as China. Civilizations labored to refine the sextant, trying different shapes and materials, such as bronze and mahogany.
Full Steam Ahead With The SextantThe prolific seafarers, the Portuguese, developed and popularized the bronze quadrant as a navigation tool. Instead of the cord that the kamal used, the quadrant employed a string, called a plumb bob. The quadrant had two downfalls: the plumb bob would fly about in heavy sea winds, and keeping the quadrant perfectly vertical on a roiling ship's deck was difficult.
Meet The SextantA wooden sextant knows as a cross-staff was revitalized by the Dutch, and it closely resembled a Christian cross. However, earlier accounts tell of a Persian mathematician who spoke of a cross-staff in his letters, indicating the technology had merely taken a long time to reach Europe. Using a cross-staff commonly made the user look as though he were 'shooting the stars', hence the modern term 'to shoot for the stars'.
Walter Henshaw crafted the prototype of the modern sextant in 1711, known as the Davis quadrant. The sextant was created shortly after, which allowed navigators to scale 60 degrees of space, versus the quadrant's 90 degrees. The first octant was made of mahogany, and allowed navigators 45 degrees of scale. While sextants were easy to use, octants were far easier, and required less prior knowledge. The Davis quadrant was replaced as standard navigation fare by the octant, and the octant was replaced by the sextant.
Why I'm A Sextant FanMost ships of today carry a sextant as a precaution, using it to navigate only when electrical GPS systems fail. When the stars or sun cannot be seen, such as during cloudy nights or foggy days, sextants are rendered nearly useless. When equatorial or polar magnetism strikes, however, sextants may be more useful than the common navigation machine. Modern sextants can be made of any material, though metal and heavy woods are preferred. Shades are also built into a sextant to prevent harsh sunlight from inhibiting a navigator's abilities.