Sailors used it to measure the height of the Polaris, or North Star. They learned from the Arabs that the height of the Polaris above the horizon changes depending on a persons Latitude, the distance above or below the equator.
The Sandglass The sandglass is also known as an hour glass, sand timer, or sand clock. It is used as a measurement for time. It is made of two glass bulbs that are placed with one above the other, and connected by a narrow tube.
One bulb is filled with sand, which flows through the narrow tube, into the other bulb at a given rate. When all the sand has reached the bottom of one the bulbs, it can be inverted to measure time again. The sandglass has a running time of 1 hour. The Nocturnal The nocturnal was a navigational tool used to tell time by the celestial clock, or stars. One ring was set to the date, the Polaris was sighted through the hole in the center, and the arm was swung around to align with pointer stars - stars in the Big Dipper, Little Dipper, or Cassiopeia.
Where the arm crossed the marked ring, the time was read. The device was also used to measure Polaris's distance in minutes of arc from north so a correction could be applied to it. Magnetic Compass The Polaris served as the seaman's lodestar, or the star that shows the way. The magnetic stone, which was used to magnetize the compass needle, was called a lodestone. Christopher Columbus was kind of a bastard. Still, here we are years later celebrating his accidental discovery of San Salvador.
So in honor of navigation and discovery—things that actually deserve adulation—here are six awesome nautical exploration tools, past and present. The quadrant, sextant, and astrolabe wer the most prominent navigation tools of Columbus and the sailors who followed him during the Age of Discovery in the 16th and 17th centuries. When using the quadrant, sailors would locate the North Star with the viewfinder, and a weighted string would align itself with a degree marking telling you the angle between the star and the horizon.
The sextant used an adjustable dial, as opposed to string, but ultimately, they all provided a working latitude for sailors. Christopher Columbus used his knowledge of lunar cycles to trick natives on San Salvador into giving him food and shelter. They believed he could make the moon disappear forever and cause doom and destruction. Columbus got real lucky and his bluff worked. Maybe you can use the lunar calendar for something less malevolent, like learning the position of the moon so that you can better use your sextant.
Allegedly used by the Olmec in Central America around B.
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