Archaeoastronomy owes its emergence in the 1970s largely to the furor caused by the controversial and often spectacular claims made by Alexander Thom and others about astronomical alignments at British megalithic monuments. Although archaeoastronomy itself soon grew to encompass a much wider range of evidence, “alignment studies” remain at the heart of a great many archaeoastronomical investigations, particularly those concerning prehistoric Europe.
Where we are searching for evidence of astronomical concerns in prehistory, alignments of monumental architecture remain at the forefront of most investigations. Yet alignments can arise fortuitously, since every oriented structure must point somewhere. Hence the importance of repeated trends, which can be identified and/or verified statistically; good exemplars are the short stone rows in western Scotland and the recumbent stone circles in eastern Scotland. (The stone circle at Drombeg in Ireland provides a cautionary case study.) On the other hand, where other types of evidence are available to us (such as written documents or ethnohistory), studies of the significance of particular alignments may be carried out in a broader context with little or no need for statistical verification. A good example of this is the alignment of the so-called Governor’s Palace at the Maya site of Uxmal.
The term alignment studies is not limited to the architecture of large monuments and public buildings but also includes studies of the layout of cities, as in pre-Columbian Mesoamerica (Teotihuacan, for example) or the ancient classical civilizations, and their possible relationships to celestial objects.