Humanity has always found themselves entranced with the heavens and stars. Using the sun and stars, ancient people could navigate their journeys accurately. Both land and sea could be traversed using this navigation method. As the study of the stars and sun for navigation was refined, mathematical equations and constant measurement were required.
The stars and arrangement of the heavens have always fascinated humankind. Using the sun and stars,
ancient people could navigate their journeys accurately. This navigation method was utilized both on land and in the sea. Constant measurement and mathematical calculation was required as the study of navigation using the stars and sun grew more complex. 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. Commonly, astronomers and mathematicians were one and the same. Using their thumb and finger as a rudimentary sextant, the Arabs were the first to employ the concept, followed by the Chinese and Byzantines. The kamal, a square sextant with a cord, was developed later 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.
The quadrant would be popularized by the Portuguese, who were prolific sea navigators. Similar to the cord of the kamal, a string, called a plumb bob, was used in the bronze quadrant. The fact that the plumb bob would fly about in heavy winds and that keeping the quadrant perfectly vertical during the rocking motions of a ship both contributed to the quadrant’s downfall.
In the 1800’s, the Dutch popularized a style of sextant known as the cross-staff, which was made of wood and strongly resembled a Christian cross. The earlier letters of a Persian mathematician, however, reveal that Persia knew of the cross-staff, but that it had taken decades 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’.
In 1711, Walter Henshaw crafted the forerunner of the modern sextant - known as the Davis quadrant. Created shortly thereafter, the sextant enabled navigators with a scale of 60 degrees. Mahogany octants were introduced as well, which allowed 45 degrees of scale. While sextants were easy to use, octants were far easier, and required less prior knowledge. The octant first replaced the Davis quadrant as standard navigation fare, and the octant was later replaced by the sextant.
Today, sextants are kept onboard most ships as a back-up navigational tool in case electrical GPS systems shut down. They are also commonly used by collectors and nautical enthusiasts as
nautical wall decor. Conversely, sextants rarely work during foggy or excessively cloudy nights when the stars or sun cannot be seen. When equatorial or polar magnetism strikes, however, sextants may be more useful than the common navigation machine. While made of most any material, modern sextants are preferred to be constructed of metal or heavy wood. Bright sun damages a navigator’s ability, and shades are built into a sextant to prevent issues.
