Like meteorological and seismological prognosticating, foreknowledge of astronomy has its practical side–at least it did in the Mesoamerican world. The tedious job of laying out an eclipse or Venus prediction table, and the collaborative effort involved in setting up an architectural alignment to the rising sun were part of any competent Maya court astronomer's job description. The end product, whether written document or standing architecture, bore direct relevance to the scheduling of civic, social, and environmental events. State politics depended on it.

This collection of five papers, three focused largely on the Mesoamerican (especially Maya) written record and two on the unwritten (archaeological) data, reflect the reasons why the interdiscipline of “archaeoastronomy” has undergone its name change to the more relevant-sounding “cultural astronomy” over the past two decades.

Agro-astronomy, the connection between astronomical observation and the planting cycle, is a topic that Milbrath already has been exploring via the examination of iconographic representations presented in a seasonal context in the codices. The connection in her paper deals with evening star Venus and eclipse observations. Given its prominence in the daytime sky close to the sun during totality, one might anticipate that the Maya would regard it, in a sense, as perpetrating the eclipse. Milbrath challenges earlier interpretations of an almanac in the Madrid Codex, which suggested that it refers to a series of eclipses that occurred five centuries prior to the date of the document. Alternatively, she proposes that the eclipses were observed at times contemporary with the document and, moreover, that they were paired. She argues further that the almanac encodes a repeatable pattern of Venus, eclipse, and agricultural cycles that span the second half of the fifteenth century. Additionally, Milbrath's wealth of detail on contemporary agricultural cycles and climatic variations in the ecosphere offer a bonus contribution to the cultural aspects of Maya astronomy.

Commensuration, the search for large numbers exactly divisible by smaller ones of astronomical or ritual importance, is known to have been paramount in Maya daykeeping, a theme already invoked in Milbrath's paper. In a more theoretical contribution that also deals with eclipses, Justeson draws heavily on this seminal principle of Maya cycle building, as he continues to address the question: how might the Maya actually have gone about creating a well-known warning table in the Dresden Codex, i.e., a formalism to anticipate the occurrence of eclipses?

Justeson's model is based on computed data on actual eclipses that span a thousand years from the Preclassic to Late Classic periods (2000 b.c.–a.d. 900). His correlation-free model reveals several hitherto unknown, repeatable families of eclipses, most important among them an 88-month cycle separated by 405 months, which corresponds to the actual length of the Dresden Table. Justeson utilizes his model to investigate how the eclipse stations in revisable versions of the Dresden document actually might have been drawn up. Justeson's theoretical modeling technique has the advantage that it can be used to address other problems; e.g., how, given what we already know about the principles that governed their methodology, Maya astronomers might have gone about tabulating other long-term periodical cycles, such as the precession of the equinoxes.

The more epigraphers look into astronomical references in pre-Columbian Mesoamerican documents, the more solid connections they begin to discover across codices and cultures. Comparative studies now make it clear that the scribes of one region were well in contact with those in another, often communicating their computational skills and sharing ways of formatting almanacs. Vail expands on her seminal studies of astronomical cross-references in the codices with a paper on further Venus associations, including rain, hunting, war, and the concept of twinness. She finds similar iconography and calendar dates in an almanac in one Maya codex (Madrid) that are identifiable with a better-known Venus reference in another (Dresden). Vail's work also uncovers cross-references between Maya and central Mexican documents. Given that such parallels exist, why not look farther afield? Vail does so with the Morning/Evening Star dichotomy by offering possible connections between the morning and evening star aspects of Venus twins as a single god of war and the War Gods of the Zuni cultures in the American Southwest.

There is very little technological evidence on Maya methods of mensuration, other than the possible use of crossed sticks and zenith tube devices (rather than gnomons) related to the timing of solar events and calendars in Mesoamerica. On the other hand, there is good evidence of the use of alignments incorporated in specialized architectural assemblages to mark astronomical events. The paper by Piñeda de Carías et al. explores a possible physical means the Maya could have used to segment the seasonal year. Their investigation focuses on Copan's Stela D, which is prominently located at the northern end of the Plaza of Copan, suggesting that it could have functioned as part of a solar shadow-casting device. Incorporating the proximate stairway and the sculpture surrounding it, shadows cast by Stela D are shown to mark to the solstices, equinoxes, and solar zenith passages, all of which are acknowledged to have been given attention by Maya daykeepers. While a hypothetical arrangement such as that posited by Piñeda de Carías et al. seems to work, the argument for intentionality could be greatly strengthened by archaeological contextualization.

Lastly, Dowd et al.’s paper is concerned with an excavated example of a specialized form of architecture at Calakmul to mark sunrise positions on important dates of the seasonal year. The Calakmul complex, like others in the category of so-called E-Groups, after the Uaxactún prototype, deviates in orientation from the typical solstitial and equinoctial positions. The discovery, measurement, and assessment of a number of similarly deviated structures raises the question: were all members of this class of functioning observatories, or could they (or perhaps some of them) have been only commemorative allegories? Further, did any of these structures play a role in reforming the calendar by having their alignments later directed toward alternative seasonal dates? Notwithstanding, the archaeological data support the hypothesis that at least a solstice alignment at Calakmul was intentional. A proposed building sequence consistent with these data is articulated to support that observation.

In sum, the significance of the studies that comprise the collection address a topic once confined to the purely esoteric realm of Maya philosophy and religion. The papers focus on some of the more practical aspects of Maya timekeeping reflected in the study of astronomy in culture. The investigators propose viable links between sky phenomena and social, environmental, and other aspects of daily life, each stressing the interdisciplinary aspects of Mesoamerican research. The collection gives us a behind-the-scenes look at the role of the astronomer. Far from being squirreled away in remote reaches of the palace solely to contemplate the behavior of the ancestor gods, the Mesoamerican skywatcher emerges as a skilled professional in tune with the direct needs of those he or she served.

I am deeply grateful to Anne Dowd for all of the work she put in on the Special Section from start to finish.