Archaeoastronomy is best defined as the study of beliefs and practices concerning the sky in the past, and especially in prehistory, and the uses to which people’s knowledge of the skies were put. It can be misleading to think of archaeoastronomy as the study of ancient astronomy, since people in the past might have related to the sky in very different ways from people in the modern Western world. For this reason many people prefer to avoid the word astronomy altogether. Some speak of astronomies to emphasize this point, as is evident in the title of topics such as Astronomies and Cultures.
There have been scientific investigations of the possible astronomical significance of spectacular ancient monuments ever since the later nineteenth century—in the work of Sir Norman Lockyer and Alexander Thom, for example. However, the term archaeoastronomy has only been in existence since 1969 and soon thereafter came to take on a much broader meaning. Some popular authors such as Gerald Hawkins, whose topic Stonehenge Decoded brought Stonehenge into the limelight in the mid-1960s, preferred the term astro-archaeology, and this for some became synonymous with alignment studies, causing a good deal of confusion that has still not entirely abated. Nonetheless, it was archaeoastronomy that emerged as a recognized academic “interdiscipline” a decade later, marked most significantly by the appearance of two academic journals: Archaeoastronomy: The Journal of the Center for Archaeoastronomy in the US and, in the UK, the Archaeoas-tronomy supplement to the Journal for the History of Astronomy. It was also signaled by a landmark international conference in archaeoastronomy at Oxford in 1981, the first of a series that has continued ever since.
By that time, archaeoastronomy had already expanded beyond the mere study of monumental alignments. This development was led from the Americas in the 1970s, particularly by studies of astronomy in pre-Columbian Mesoamerica. These studies leaned heavily upon ethnohistorical evidence—the writings of chroniclers in the early years after European contact and conquest—and also, at least in the case of the Maya, upon written evidence in the form of native “topics,” most notably the Dresden Codex. Alignment studies formed an important part of the new integrated approach to studying Mesoamerican archaeoastronomy but did not drive it. On the other hand, European and especially British archaeoastronomers in the 1970s were largely obsessed with archaeological and statistical reappraisals of Alexander Thom’s work and were busy developing formal fieldwork procedures and quantitative techniques for resolving the huge controversy surrounding Thom’s conclusions. The American archaeoastronomer Anthony Aveni would later come to characterize these two contrasting approaches within archaeoastronomy as “brown” and “green,” after the colors of the covers of the two volumes (Archaeoastronomy in the New World and Archaeoastronomy in the Old World, respectively) that emerged from the 1981 Oxford conference. Finding the right balance between these two methodological approaches remains one of the major challenges for archaeoastron-omy to this day.
Archaeoastronomers, then, are prepared to consider a range of types of evidence—not simply archaeological—and they certainly do not restrict themselves to alignments of monuments. In this sense the word archaeoastronomy is misleading, even though it is the term that has stuck. Furthermore, there is no clear boundary between the past and present. Almost from the outset, “brown” archaeoastronomers who studied astronomical traditions within North America realized that myths and traditions surviving in modern indigenous Native American groups could be highly relevant to our understanding of astronomical traditions of the past. When we study reports of ethnographers who worked, say, fifty years ago on a tradition that has since died out, it is clearly pointless to worry about whether to classify this as ethnohistory or ethnography. We may even be able to identify longer threads of continuity stretching from the past into the present, so that, for example, the study of a modern Andean village such as Misminay in Peru may give us some insights into worldviews prevailing in Incaic or even pre-Incaic times. In short, what was once (and sometimes still is) identified as ethnoastronomy blends seamlessly into archaeoastronomy. Many would prefer simply to combine the two fields of study, referring to them together by a term such as cultural astronomy.
Why was archaeoastronomy so controversial in its formative days in the 1960s and 1970s? Partly because Thom’s own interpretations, though based upon high-quality surveys of many hundreds of British megalithic sites and supported by rigorous statistical analysis, struck most archaeologists as clear examples of ethnocentrism. In seeing prehistoric Britain as populated by “megalithic man” whom he described as “a competent engineer with an extensive knowledge of practical geometry,” Thom was merely seeing his own reflection in the past, the skeptics claimed. In like manner, they pointed out, several prominent astronomers were seeing their own reflections when they described Stonehenge as a sophisticated observatory and eclipse predictor. But there was also a deeper reason. In the 1970s, most archaeologists in the forefront of theoretical developments were trying to describe the actions of human communities in prehistory and the processes of social change in terms of human responses to ecological or environmental constraints. These “processual archaeologists” saw no reason why prehistoric people would have bothered incorporating astronomical alignments into communal monuments.
In the decades that followed, both archaeoastronomy and theoretical archaeology moved forward. Archaeoastronomy ceased to be dominated by astronomers and began to incorporate more archaeologists and anthropologists. This would, at the very least, help to avoid naive pitfalls such as eth-nocentrism. As a result, archaeoastronomy began to lose its cavalier attitude toward the body of theory that had been developed (and was continuing to develop) within archaeology and anthropology for interpreting the actions of any past community from what we can find in their material remains. At the same time, the so-called “post-processual” revolution was taking place in theoretical archaeology. A new generation of archaeologists was beginning to confront issues such as cognition. What was going on in people’s minds, claimed these interpretative archaeologists, was just as vital in determining people’s actions in the past as any environmental constraints. Put another way, how a group of people viewed the world— their cosmology—was just as important in determining their actions as what a modern archaeologist might consider “rational” considerations. This conclusion was supported by numerous case studies from modern indigenous communities such as the Hopi and Pawnee in North America. To speak of “rational” behavior is itself ethnocentric, since what we consider rational is a product of our own worldview.
Why are archaeoastronomy (and ethnoastronomy) worth doing? If we want to understand more about why certain human communities did what they did in the past, then we need to try to understand aspects of their cos-mologies—the ways in which they perceived the world. Astronomy is an essential part of nearly every cosmology, because all human communities have a sky, and the sky and the objects in it form an integral part of the perceived world. The objects in the night sky are immutable, regular, reliable, predictable; for communities who did not live inside brightly lit buildings and whose skies were not polluted by modern city lights, they were there for people to watch and contemplate night after night, season after season. They become imbued with meaning.
But what different groups of people perceive as important in the sky, and what significance they ascribe to it, is highly culture-dependent. Two good examples that illustrate this in different ways are the calendar of the Borana of Ethiopia, and the emu “dark cloud constellation” recognized by certain Aboriginal groups in Australia. Nevertheless, people generally try to keep their actions in harmony with the cosmos as they perceive it, which may be the reason many prehistoric monuments were deliberately aligned with objects in the wider landscape, including objects in the sky. Recognizing associations that certain human communities considered important can help us understand something of the worldviews that gave rise to them.
The advantage that the sky holds for us in trying to spot such associations is that it forms a part of the ancient environment that is directly accessible to us, unlike the terrestrial landscape, which is often transitory. We can use modern astronomy to reconstruct, with considerable accuracy, the appearance of the night sky at any place and time, including the motions of the sun, moon, stars, and planets. And this capability offers a considerable advantage, whether we are concerned with myths and beliefs relating to the sky, monumental alignments upon celestial objects, or other kinds of evidence.
