By the 16th century, the "Age of Exploration," advances in celestial navigation enabled mariners to measure the angle of the sun and stars to determine their latitude (their location on the Earth north to south) but not their longitude (their position west to east). These early explorers could never truly know their precise position at sea.
Dead reckoning, often used as a last resort today, was one of the few navigation techniques available for ancient mariners. This method requires the navigator to factor in the compass direction, speed, currents, and other information to track and determine the vessel's location. It also requires meticulous observations and careful record keeping on a chart. Errors in a log could often result in a prolonged voyage at best - and at worst... disaster.
New technological developments such as the marine sextant and the sea-going clock in the 18th century made ocean passages routine. The advent of airplanes in the early 20th century sparked a new interest and energy in the field of navigation. Calculations now had to be made not for the speed of ships, but for the speed of airplanes.
Captain Philip Van Horn Weems was instrumental in revolutionizing modern navigation and was an active participant in navigational advances from the time of his sailing cruise aboard the USS Hartford in 1909 to his patent in 1961 of the space navigation sphere.
The advent of computers, satellites, the Global Positioning System, and electronic navigation has revolutionized the ways in which navigators ply the oceans, fly the skies, and explore space in the 21st century. Navigators at sea today are more likely to remain below deck at a computerized navigation station than on deck observing the stars.
Everyone who travels on land, sea, or in the air and in space should appreciate understand, and perhaps even practice the "art" of navigation using the methods of old to gain an appreciation of the work of those who came before us.
