Observatories, like so much of astronomy, are truly ancient features of human culture; retracing the steps of the first person to stand on a sacred hillside and search the sky for answers is truly an impossible task. Across the globe, however, such sites — devoted to deciphering the heavens — are found in considerable numbers. Unlike modern mountaintop facilities that probe the entire spectrum of light with computerized equipment, ancient observatories were placed in positions for optimal viewing with the eyes — on hilltops or atop structures such as the ziggurats of ancient Babylon or the rooftops of Mexico’s Monte Alban.
Ancient observatories often employed reference markers to the seasonal procession of the natural calendar; consider, for example, the familiar stone pillars of Stonehenge or the spokes of Native American medicine wheels. Such places were of considerable spiritual significance; astronomers, able to predict the motions of the Sun, Moon, and planets, were considered to be interpreting the will of the gods as written on the tableau of the skies — a considerable, and occasionally dangerous, responsibility.