Mesoamerican Alignments

Archaeoastronomical alignments have been known (by Europeans) to exist in Mesoamerica since Motolinia recorded in the 16th century that the Aztec ruler Montezuma found that the great temple of Huitzilopochtli was somewhat out of line with the rising of the Sun at the equinoxes and wished to correct this by tearing down the building and rebuilding it. The first recognition of such an alignment in an archaeological site in Mesoamerica was at Uaxactun, Guatemala, where alignments are associated with the rising of the Sun at the equinoxes and solstices.

Ricketson (1928), checking on a suggestion by the well-known archaeologist Frans Blom, recognized that the equinox rising Sun, viewed from Temple EVII, rose above the center of the central building (EII) on an eastern platform at the equinoxes and that the Sun rose at the outside corners of the other two buildings on the platform (EI and EIII) at the solstices. Temple EVII is a four-sided pyramid with stairways oriented to all cardinal directions. The equinox viewing line passes directly above the stelae in front of Temple EVII, which have the Long Count dates 8.16.0.0.0 3 Ahau 8 Kankin (ST 19) and 9.3.0.0.0 2 Ahau 18 Muan (ST 20), separated by seven katuns (140 tuns or 504,000 days— three days more than 138 Ty). This is the shortest possible interval at which two katun ending dates can return to approximately the same position in the tropical year. Although these dates are not equinoxes in any correlation that has yet been suggested, if the Palenque date 1 Ahau 13 Mac is a winter solstice date, as the structure of the associated dates suggests, then these dates occur 1 to 2 days before the spring equinox and 4 to 5 days before the spring equinox, respectively, the closest equinoctial positions of any katun ending for about 1000 years (Kelley 1986).

Perhaps the most striking equinox alignment in Mesoamerica is that of the Temple of Kukulcan (Quetzal-coatl) at Chichen Itza. Here, the serpent balustrades of the Temple, lit by the setting Sun, seem to come to life and wiggle down the stairs. This hierophany, or sacred appearance, has become a popular tourist attraction since first noticed by Arochi (1976), whose book, La Piramide de Kukulcan, deals primarily with this phenomenon. Although there is no obvious way to check it, it seems likely that the temple was originally built when the equinox coincided with a heliacal rising either of Mercury or of Venus (see §12.6 on the shift of the Feathered Serpent from Mercury to Venus).

Another remarkable visual phenomenon occurs in connection with the alignment of the axis of the Pyramid of the

Sun at Teotihuacan (Broda 2000, p. 424). As viewed from the west, the axis is directed 15°21' S of east, and points to the (invisible!) Peak of Orizaba, the highest mountain in Mexico. At the winter solstice, a sun pillar appears above the peak, which is covered with an icefield, and presumably represents the vertical column above the Sun described in §5.1.4. The Pyramid of the Sun was the earliest major construction at the site, and this alignment is basic to the grid of the city and to many of the pecked circles, discussed below.

The person who did the most to determine possible astronomical alignments in Mesoamerica was Horst Hartung (1968, 1971, 1975, inter alia), frequently joined in later studies by Anthony Aveni (cf., especially Aveni and Hartung 1986). The study of major Mayan sites (Hartung 1971) is probably the most comprehensive attempt to examine the various ways in which astronomical alignments in Mesoamerica were incorporated into architectural patterns. Hartung's (1975) study is a summary of the major kinds of alignments discovered up to that time and their implications for Mesoamerican conceptions of the relationship between celestial and earthly affairs.

Among the classes of alignments pointed out by Hartung are lines marked across pecked designs, such as crosses or crosses within circles or circles; lines along the surface of a building; directions from corner to corner, especially of windows; directions from fixed observation points to structural markers such as the corners of buildings; and shafts, vertical or horizontal, through which the light of Sun, Moon, or stars might be observed at particular times. Stelae were sometimes used to mark alignments. The orientations of buildings, sometimes in sets, also served to draw attention to particular astronomically important directions. To these, we may add alignments designed to provide striking visual effects at particular times of the year.

The work of Aveni and Hartung (1986) is centered on the alignments19 of archaeological sites and buildings of the Puuc area of Yucatan, with some comparative material from elsewhere in Mesoamerica. From the entire Mayan area, they examined over 96 sites and recorded over 200 alignments. Eighty-nine percent of these alignments fell east of north with maxima at 14' E and 24' E. In the Puuc area, 44 alignments from 33 sites showed the maximum at 14', but not that at 24'. It seems reasonably clear that such figures are not a product of randomness. However, the degree of variation in these alignments is substantial.

It is perhaps not surprising in these circumstances that some of the exceptions to the general pattern provide some of the most clear-cut evidence of particular specifiable alignments. The best of all is that of the Governor's Palace at Uxmal (Figure 12.21), which looks toward a pyramid at Nohpat and the rising point of Venus at its southerly extreme.

Elaborate masks of Chac, the Rain God, so typical of the Puuc area, are numerous on the building and some of them

19 Aveni and Hartung use the terms "alignment" for any measured direction and "orientation" for those alignments that they suppose were intended by the builders to coincide with particular phenomena.

Figure 12.21. The Palace of the Governor at Uxmal: From the top of the stairs, a line of sight leads to Nohpat and to a Venus horizon location. Photo courtesy of Dr. R. Angione.
Figure 12.22. The Pyramid of the Magician at Uxmal. Photo courtesy of Dr. R. Angione.

are marked with the star or Venus glyph. An accompanying text contains a variant of the same glyph and a number of unusual glyphs that have been identified by the Brickers (1996) as constellation glyphs. Some of the Chac masks of the Governor's Palace are marked with a Venus glyph and the number 8. Aveni (1982, p. 15) and Aveni and Hartung (1986, p. 31) have suggested that this referred to the canonical eight days disappearance of Venus at inferior conjunction. The Brickers thought it was more likely in the context of the southerly and northerly extremes to refer to the eight-year cycle (§3.1.5). At the Adivino, or Pyramid of the Magician (Figure 12.22), the same combination appears, but this time there is a kin, or "day," glyph below the eight, thus, supporting Aveni. Strikingly, the characteristics of the two Venus glyphs are different.

A dispute has arisen between Aveni and Sprajc (see Sprajc 1990/1993a) over the question of whether the intent was to create a southern sunrise alignment or a northern sunset alignment. Because the alignment is nearly reciprocal20 and the Mayans must have known this, we assume that observers at Uxmal watched Venus rise over Nohpat, whereas observers at Nohpat and Cehtzuc watched Venus set, aligned with the Palace of the Governor. There is no reason we know to assume that these viewpoints are exclusive. A partly fallen pillar and a two-headed jaguar throne on top of a small square platform are also on the alignment to Nohpat. The throne could well have served as a fixed observing point to look in either direction.

At Palenque, the inner doorway of the Temple of the Cross is decorated with a bas-relief of the old black god of the underworld (God L), whom DHK has identified with Saturn. At winter solstice, the last rays of the setting Sun catch God L when all other scenes have faded into darkness. See §14.1 for parallels among the Kogi people of Colombia.

Broda (2000, pp. 414-415) discusses two examples of vertical tubes at Teotihuacan that were used to mark the zenith passage of the Sun. They are located in "caves" or tunnels used in the excavation of rock slabs for buildings. They are fully illuminated only at zenith passages, but some light enters these "caves" between April 30 and August 12, that is, for 105 days, followed by 260 days of darkness. Zenith passages occur at both Copan and Izapa on these very dates.

At Monte Alban (f = 17°03' N) and Xochicalco (18°48' N), there are vertical tubes penetrating deep into structures. These allow the direct rays of sunlight to penetrate to chambers below the bottoms of the tubes only on the two dates of zenith passage at each site, when the solar declination equals the site latitude. In these two sites, as at Teotihuacan, some light enters the chambers for the same 105-day period. Building P in Monte Alban contains the shaft among a flight of steps, visible from Building J, and aligned with a perpendicular to one face of building J, a five-sided structure (see Figure 12.23).

The section of Building J containing the steps leading down from this face is slightly skewed off this line, and a line perpendicular to the steps pointed to the rising azimuth of the star a Aurigae (Capella) in 250 b.c. The alignment was probably intentional because this star rose heliacally on one of the two dates of the calendar year in 250 b.c. (~May 12/13 according to The Sky, Red Shift, and Voyager III simulation software— see Figure 12.24)21 when the Sun passed through the zenith. If this were indeed the case, the heliacal rising of Capella might have provided a warning to priests to prepare for that festive solar passage event, still celebrated today in the region. Voyager shows haAur = +1.8°, h0 = -10.1° at 05:12 a.m., May 13.

However, our simulation shows a flat horizon; Capella would have arisen above building P, but as can be seen in Figure 12.23b and c, the horizon in this direction is certainly not flat. With increasing elevation of the actual horizon, the

20 Sprajc has found that the northern extreme during the 8th to 10th centuries a.d. was slightly greater than the southern extreme.

21 Aveni 1980, pp. 256-257, gives ~May 2 as an approximate heliacal rise date; and his Table 11 would suggest ~May 8 for solar zenith passage. Thus, the harbinger appears to work fine. However, the dates of zenith passage and the apparent helicacal rise date as obtained from simulations are later, as noted above.

date of the heliacal rise of Capella would have to be later than for a flat horizon in order to keep the arcus visionis to ^10° (cf., §3.1.5); that is, the Sun would need to have moved further eastward, away from Capella. This requirement throws some doubt on Capella as a harbinger of solar zenith passage at that epoch. Presumably, if the arcus visionis were determined to be smaller for this site (perhaps because the sky brightness was less than typical, the transparency of the atmophere higher making a star appear brighter—see §3.1), or if optical aids could have been used to observe Capella in a brightening sky, it might still have been possible. Additional investigation requires the determination of the elevation angle along the ridge of mountains on the visible horizon from the most likely observing site, presumably Building J, or some other place from which the alignments incorporated in Building J could have been used as a backsight. An alternative or additional use of the shaft may have been to note the instant of passage of the Pleiades through the zenith, which Aveni states (1980, p. 253) also occurred at Monte Alban at this time. Of course, such a passage would have occurred whenever the Pleiades could be seen, and when its declination matched the latitude of Building P, within the angular size subtended by the shaft on the sky (2° according to Aveni 1980). However, the simulation indicates that the various stars in the Pleiades had declinations between about ~1472° and slightly less than 15° in 250 b.c.; so the epoch of zenith passage was only beginning or about to begin at this time.

At the nearby site of Caballito Blanco, structure O is smaller but otherwise bears a strong resemblance to Building J at Monte Alban. Its alignments are not so clear, however. Whereas the V-shaped side of building J was aligned to the setting of the Southern Cross and a and b Centauri, the analogous point of Building O was directed to the setting of a Canis Majoris (Sirius), the brightest star in the sky. Its heliacal rising occurred just after summer solstice (The Sky and Voyager simulations suggest ~July 9), and its cosmical setting just before the winter solstice (~Dec.11), and its heliacal (acronychal) setting, ~May 21, in 250 b.c.

At Teotihuacan (f = 19°68), the zenith passage of the Sun coincided with the heliacal rising of the Pleiades about May 20 in 150 a.d., at about the time of the founding of the city (Aveni 1980, p. 225). Aveni notes that the Pleiades would have passed close to the zenith also, but this would have been far from the epoch when the coincidence was exact, that is, when the declination of the Pleiades was equal to the latitude. This circumstance took place many centuries later—at about 806 ± ~50 a.d., according to our calculation, depending on whether Alcyone, the brightest Pleiad, or another is selected, and the exact latitude of the ceremonial site from which the event was observed. Figure 12.25 demonstrates the proximity of 6 Pleiads to zenith passage, represented by the horizontal line through 0 (see Table 3.1 and §5.8.1 for the identities of the Pleiads and Figure 5.18 for their appearance in the sky).

The appearance of the Pleiades at or near the zenith may provide a partial explanation for a strange series of representations found painted on the floor of Portico 4 of a building at Tetitla within the Teotihuacan site. Jorge de Angulo

(1984) has shown that the 11 repeated diagrams on the floor constitute a giant version of the dots in each one of them and that they represent the 11 brightest stars of the Pleiades, drawn as a stylized jaguar. A jaguar in a knotted net is a very prominent feature of Teotihuacan iconography and seems to correspond to the knotted eye jaguar of the Mayas. Kelley (1980, p. S24) has suggested that the Aztec equivalent of this deity was Mixcoatl (literally, Cloud Snake) and that he was equated with Jupiter. Mixcoatl is said to have created 400 Chichimecs, in order that they might be killed by his children to obtain blood to feed the sun, and it is said that he himself became one of the 400 (Garibay 1965, ed. Historia de los Mexicanos por sus pinturas, pp. 36-37). They are also referred to as the 400 Mimixcoa,22 killed by their sister, Itzpapalotl, the Obsidian Butterfly, and Brundage (1979, pp. 130-139) also equates them with the 400 Southerners, led by the goddess Coyolxauhqui. They are attacked and killed by their brother, Huitzilopochtli, who decapitated Coyolxauhqui and rolled her down Snake Mountain so that she broke in many pieces. The battle between Huitzilopochtli and the 400 Southerners is sometimes described as a midnight game in a ball-court. Brundage regards all the actors as figures in the sky—Coyolxauhqui as the moon, Mixcoatl perhaps as a version of Venus or the Sun—but he makes no attempt to interpret the story in an astronomically coherent fashion. Mixcoatl is also said to be the inventor of the intoxicating pulque, usually attributed to the Moon goddess, Mayauel, the associate of the Four Hundred Rabbits of drunkenness (Brundage 1979, pp.

22 Plural of Mixcoatl. The number 400 may be significant in being both a Mesoamerican round number (20 x 20) and a close approximation to the number of days in the synodic period of Jupiter (398$).

Figure 12.23. Monte Alban: (a) The plan view of the site. Drawing by Sharon Hanna. (b) Photographic overview— Building J is in the foreground. (c) A magnified view centered on Building P, which contains a vertical shaft among a flight of steps, possibly to mark the zenith passage of the Sun. Photo courtesy of Dr. R. Angione.

Figure 12.24. The simulations of the heliacal rise of Capella (a Aurigae) on the mornings (a) May 2 and (b) May 12, 250 b.c., at Monte Alban, Mexico, according to Red Shift (see Appendix A for details of the sky-simulation packages): The Sun is shown on the ecliptic and below the horizontal line representing the horizon. The distance of the Sun below the horizon should be between 10° and 25°, and the star heliacally rising should be high enough to overcome both the high extinction and the sky brightness close to the horizon, and, of course, elevated features on the horizon. The former circumstances should require at least a degree or two in the case of Capella; the latter, many degrees. Notice that Capella could not have risen heliacally as early as May 2.

Figure 12.25. The zenith distance at a transit of six stars of the Pleiades at Teotihuacan (see Table 3.1 and §5.8.1 for the identity of the Pleiads and Figure 5.18 for their appearance in the sky) at Teotihuacan. Calculation and plot from a Lotus 1-2-3 spreadsheet by E.F. Milone.

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