William Andrews, former curator of the now-defunct Time Museum and a master clockmaker, is trying to build an advanced sundial that melds horology, cartography, and a passion for antique scientific instrumentation. His Longitude Dial was inspired by a 1610 map created by mathematician Franz Ritter. That map and Ritter's others are considered the first examples of a gnomonic map projection, a method to accurately represent the curvature of the earth on a flat surface. In the new issue of Smithsonian Magazine, Dava Sobel, author of the critically-acclaimed book Longitude and other works, profiles Andrews and the maker mindset behind his unusual project. From the article:
"My original goal in this," he said… "was to produce an accurate timepiece with no moving parts–an original creation that combined art and science, drawing from the long traditions of both in its design, and incorporating the finest craftsmanship and latest technology in its construction." What really set his idea apart, however, was his intention to base the dial on an unusual type of map, and to center the map on the very spot where the dial would stand. The map's meridians of longitude would serve as the sundial's hour lines, creating a union of time and space for that particular location–something no dialist or clockmaker had ever before achieved…
Today the work of measuring precise time has been relegated to government agencies such as the U.S. Naval Observatory in Washington, D.C., the International Earth Rotation Service at the Paris Observatory and the Bureau International des Poids et Mesures in Sevres, France, all of which measure a second by the interval it takes a cesium atom to vibrate 9,192,631,770 times. Because the Earth goes its own way in space, however, heedless of atomic time, "leap seconds" are periodically added to our years to keep our clocks in sync with the turning of our planet. A sundial requires no such adjustment. "A sundial lets you see the Earth turn," Andrewes says. "Of course you know it's turning, but when you witness the shadow moving across the dial you feel something. Many people have no idea why the seasons occur–that the hemisphere tilted toward the Sun actually changes from winter to summer. Time has become separated from space, and I think that's a mistake."
