It is known that the grid pattern characterizing the city layout of Teotihuacan incorporates two slightly different groups of alignments, skewed approximately 15.5° and 16.5° clockwise from cardinal directions. I argue that these alignments were dictated by deliberate and astronomically functional orientations of the Pyramid of the Sun and the Ciudadela. The two structures recorded sunrises and sunsets on two different sets of dates, allowing the use of an observational calendar composed of intervals that included multiples of 20 days and a 260-day period. The evidence presented suggests also that the location of the Sun Pyramid was not determined by the cave that is now underneath the structure and is probably human-made, but rather by a combination of astronomical and topographic criteria: the place allowed the temple built there to be oriented both to sunrises and sunsets on significant dates and, in the perpendicular direction, to Cerro Gordo to the north; furthermore, sunrises on the so-called quarter-days of the year could be observed from the same spot over a prominent mountain on the eastern horizon. The dates corresponding to the Teotihuacan alignments are attested also at other central Mexican archaeological sites and must have been employed, primarily, for scheduling agricultural and associated ritual activities in the yearly cycle.

Arheološko najdišče Chactún, ki leži v vzhodnem delu mehiške zvezne države Campeche, smo odkrili leta 2013 v južnem delu obsežnega arheološko neraziskanega ozemlja, ki se razteza med regijama Río Bec in Chenes. Urbano jedro nekdanjega mesta sestavljajo tri koncentracije monumentalne arhitekture, med številnimi kamnitimi spomeniki pa je več takih, na katerih so ohranjeni reliefi. Sodeč po obsegu in velikosti stavb, je Chactún eno največjih majevskih mestnih središč, doslej znanih v osrednjem nižavju polotoka Jukatana. Medtem ko keramika razodeva poselitev od predklasične dobe naprej, stele s hieroglifskimi besedili in datumi kažejo, da je mesto doseglo svoj vzpon v pozni klasični dobi, ko je dobilo pomembno vlogo v regionalni politični hierarhiji. Glede na to, da najdišče leži nedaleč od osrednjega dela območja Río Bec, je presenetljivo, da njegove značilnosti kažejo na veliko tesnejše povezave s tradicijo Petén. Posebnost Chactúna so kamniti spomeniki z reliefi, modeliranimi v štuku, sekundarne lege mnogih stel in oltarjev pa razodevajo, da je bilo naselje prizorišče dejavnosti tudi še v stoletjih po največjem razcvetu.

In a recent comment Michael Smith argues that the cosmological interpretations of Maya urban layouts proposed in an article by Ashmore and Sabloff are vague and unconvincing. He also summarizes some other comparable studies in order to show that arguments for the cosmological significance of archaeologically recovered urban patterns are, in general, subjective and lack methodological rigor. I argue that his view is an unwarranted generalization and that his references to some archaeoastronomical interpretations do not adequately reflect the advances in this field of research and its relevance for the understanding of ancient city plans. I summarize the results of several studies in Mesoamerica, focusing on Teotihuacan and the Templo Mayor of Tenochtitlan discussed by Smith, to show that rigorous methods not only have been applied in archaeoastronomical research but also have resulted in explicit conclusions about specific aspects of worldview and political ideology underlying Mesoamerican architecture and urbanism.