WHEN I HEARD THE LEARN'D ASTRONOMER 



When I heard the learn d astronomer, 



When the proofs, the figures, were ranged in columns before me, 



When J was shown the charts and diagrams, to add, divide, and measure them, 



When I sitting heard the astronomer where he lectured with much applause in the lecture-room, 



How soon unaccountable I became tired and sick 



Till rising and gliding out I wander'd off by myself, 



In the mystical moist night-air, and from time to time, 



Looked up in perfect silence at the stars. 



WALT WHITMAN (1865) 



charts and mathematics sickened 

 Walt Whitman over a hundred years 

 ago, imagine how he would feel in 

 today's electronic world. If the great 

 American poet were a sailor, he might 

 find himself not looking up in silent 

 awe at stars strewn across the heavens 

 but rather casting his gaze downward at 

 a handheld gadget that communicates 

 with satellites to fix a position on Earth. 



How soon unaccountable would he 

 grow tired and sick of that? 



For many boaters, a global 

 positioning system (GPS) receiver 

 makes the most sense. When navigating 

 the sea, they want a quick and sure lock 

 on their whereabouts. The U.S. 

 Department of Defense's GPS satellites 

 orbiting the planet provide just that. 



But what if the satellites fail? If the 

 boat loses power? If the vessel sinks? 

 What then? 



In these situations, folks at sea can 

 turn to a time-proven method called 

 celestial navigation or navigational 

 astronomy. Using Whitman's very 

 same stars — and a handful of other 



celestial bodies — navigators find their 

 position and plot a course for their 

 destination. 



A BRIEF HISTORY OF 

 NAVIGATION 



M n's first forays into the 

 sea must have been accompanied by 

 trepidation, for how could the sailors 

 know what lay beyond the vast waters? 

 Seamen of many cultures ventured out 

 only far enough to navigate by the 

 coastline and its features. If they drifted 

 into the wide open sea, they were at a loss. 



But our curiosity got the best of 

 us, and enterprising sailors tried just 

 about anything to navigate the oceans. 

 At least one ancient Norseman used 

 birds to find land. After feeding a raven 

 only enough to stay alive, the resource- 

 ful sailor released the bird when he 

 thought land should be near. If the bird 

 hovered above the ship, he knew land 

 was not close by. If the bird flew away, 



he knew it was headed for food — and 

 land. The Nordic sailor then set his 

 course by the bird's direction of flight. 



Other peoples, such as the Poly- 

 nesians, developed primitive systems of 

 celestial navigation. Kupe the Seafarer, 

 considered the Christopher Columbus 

 of Polynesia, established routes by, for 

 example, keeping the Pole Star to one 

 side of the boat and turning toward 

 another designated star when arriving at 

 the equator (which the Polynesians 

 called the Navel of Space). 



Even Columbus himself could not 

 determine his course with precision. To 

 read the heavens, he used a compass, an 

 astrolabe (a crude device for calculating 

 the position of stars) and a quadrant (an 

 instrument for measuring altitude). 

 Other navigators used instruments such 

 as the cross-staff, which also measured 

 the altitude of celestial bodies. How- 

 ever, because none of these mechanical 

 pieces was very accurate, celestial 

 navigation long remained an inexact 

 science. 



Continued 



COASTWATCH 15 



