Now, though, thanks to the man-made stars we navigate by, "the whole world is synchronized." We humans are synchronized. The problems faced by those early explorers have been solved using that time-honored combination: ingenuity, and math.
"Time and Space" is one of the most ambitious exhibits Air and Space Museum has yet put on -- in part because it involved a collaboration among curators at different Smithsonian institutions (Air and Space as well as American History), but also because the exhibit is so theoretical in its topic and scope. It's not so much about a particular time or trend, but about, you know, space and time ... and humans' place between the two. So one particular challenge the curators faced was to make the story of navigation -- a story, ultimately, about mathematical calculations -- accessible to the range of people who come through the museum every day. They tackled it well. The tale is arranged chronologically, but also in sections: navigation in the sea, navigation in the air, navigation in space, navigation in the contemporary world. We see models of clocks designed by Galileo. We see Charles Lindbergh's sextant. We see the updated sextant used by Apollo astronauts to navigate using the stars. We see a GPS-guided glide bomb. We see a duplicate of the Mariner 10 space probe, the first craft to reach Mercury. We see Stanley, the early self-navigating car.
Below, courtesy of the Smithsonian, are some of the artifacts featured in "Time and Navigation." For more, here's the online version of the exhibit.
This timekeeper was the first American-made marine timekeeper taken to sea. William Cranch Bond, a 23-year-old Boston clockmaker, crafted it during the War of 1812. This artifact is part of the National Museum of American History's collection.
Bygrave Position-Line Slide Rule
Celestial navigation requires complicated computations. Performing these calculations in cramped open cockpits with low temperatures and wind speeds of over 160 kilometers (100 miles) per hour was part of what made navigation difficult in the early years of aviation. Thankfully, Capt. L. C. Bygrave developed this handy slide rule shortly after World War I. It provided the best shortcut method of speeding up celestial computations at the time.
Navigating in the sea: this sextant was one of the navigation tools invented in the 18th century by British mathematical instrument makers that permitted mariners to find their position much better than ever before. The sextant became the most essential instrument for celestial navigation, used to find the angle of a celestial body above the horizon. Jesse Ramsden, who made this sextant, also devised a machine to divide the scale on the sextant very precisely.
Apollo Sextant and Scanning Telescope
Navigating in space: to determine position in space, an Apollo astronaut located a specific star using a single-power, wide-field telescope and then took a fix using a sextant. While this instrument does not look like a traditional sextant, the basic procedure is descended from centuries-old methods used by navigators at sea and in the air.
Dutch Pendulum Clock
In the 17th century, several inventors were trying to make an accurate clock for finding longitude at sea. In pursuit of a sea clock, Christiaan Huygens, a Dutch mathematician, changed timekeeping forever when he patented the first working pendulum clock in 1656 and later devised a watch regulator called a balance spring. Pendulum clocks immediately became the best timekeepers for use on land, but they didn't work accurately on a heaving ship's deck. Huygens worked with several Dutch clockmakers, including Johannes van Ceulen, who made this table clock around 1680. It is one of the earliest clocks with a pendulum.
Longines Sidereal Second-Setting Watch
Before 1927, watches used with sextants for celestial sightings could only be set to the minute. A watch error of 30 seconds caused a navigational error of up to 12 kilometers (7 miles). In 1927, P. V. H. Weems devised a watch with an adjustable second hand that could be set using radio time signals. This was one of his personal navigation watches. Sidereal refers to the watch running on a celestial day (about 23 hours, 56 minutes), rather than the 24 hour solar day.
Lockheed Vega 5C Winnie Mae
Wiley Post's Winnie Mae circled the globe two times, shattering previous records. The first time was in 1931 with Weems associate Harold Gatty as lead navigator. The second was a solo flight in 1933 assisted by "Mechanical Mike," one of the world's first practical autopilots.
Stanley Autonomous Vehicle
This autonomous vehicle, named Stanley, was developed by the Stanford Racing Team. Stanley is a 2005 Volkswagen Touareg modified to navigate without remote control and without a human driver in the seat. Stanley won the 2005 Grand Challenge, a robot race sponsored by the Defense Advanced Research Projects Agency (DARPA), by successfully navigating 212 kilometers (132 miles) across desert terrain.