WHITECROW BORDERLAND

Mayan Astronomy

Note 11: The Zero Base-Day in the Maya Calendar. 6/29/99

Arguing a definitive temporal position in real time, a specific Julian Day number for instance, for the zero base-day of the Maya Long Count (LC), or Initial Series (IS), notation in relation to the European calendrical system can only be said to make sense from an astronomical point of view, or if the ground on which it rests is defined by celestial events that can be fixed certainly in actual time. Depending on any other criterion would render the attempt of pinning it down to a specific place in time meaningless since no other historical or social or scientific ideology describes features that occur at predictable intervals of time in anything except ones that are determined by human perception and bias or by human activity. Intervals between celestial events, while they might be observed by, counted by, and interpreted by human beings, nevertheless do not depend on human agency as a determining factor in when or how often or how rarely they occur in real time. Since it is now possible, and a relatively simple matter as well, to see the sky as it would have appeared to people in the ancient world from any fixed location on the surface of the earth, using computer generated planetarium software, for instance, and to see the sky on any given day in the past over any extended period of time during that past, one would expect to see new kinds of arguments emerging in support of this or that fixed position for the zero base-day of the Maya calendrical system in relation to Eurocentric astronomical methods of notation.

This has not been the general rule, however, because most Maya scholars have settled on the determining factors of the Goodman-Martinez-Thompson correlation as providing a fixed point in time which generates an adequate system of astronomical positions for Maya Long Count dates that seem to be, and might as well be accepted as, consistent with ethnohistorical fact. In other words, because the GMT correlation can be associated with some modern Maya practices, as observed by Paul Goodman and others in the Maya area during the first half of the twentieth century, and because it also reflects certain standards of consistency with sixteenth century Maya paradigms observed and preserved by the Catholic priests whose duty it was to convert the Mayas to the religious ideology of the conquering Europeans, and finally, because social and cultural concerns in a purely historical context have always been more important than astronomy in the subsequent use to which the correlation has been put by European scholars, the GMT correlation as it now stands as link between Maya LC dates and Eurocentric calendrical and historical perceptions is perfectly adequate to the tasks that have been assigned to it. Since every LC date in the GMT correlation produces astronomical data, as every date must because the sun, moon, and visible planets are always already somewhere in the sky relative to each other on every conceivable day in time, the people who are inclined to deal with that aspect of Maya research have more than enough to report, discuss, and debate. From a purely historical point of view, if the correlation produces a false return in establishing the link between a Eurocentric date and a Maya LC position, nothing of significance is lost in making a social or cultural description about the nature of this or that artifact. Making an argument about dynastic kingship in Palenque during the Classic Period is not seriously altered if the dates assigned to this or that king's reign are incorrectly stated by 10 days or fifty years, since the length of the reign is perceived as being more important than precisely when it occurred in real time.

With respect to astronomy, however, the same kind of argument cannot be made at all. Being wrong by a single day in making a correlation between Maya time and the European calendar renders any statement made about the subject essentially meaningless from the point of view of native American perceptions of reality. In short, if the GMT correlation is incorrect, everything that has been said about the astronomy of the LC positions recorded by the Mayas during the Classic Period does not tells us anything at all about how the Mayas perceived the sky. It does, however, tell us precisely how Europeans believe the Classic Period Mayas perceived the interaction among the sun, moon, and visible planets. GMT astronomy is just precisely that, and nothing else, as long as there is any reasonable question concerning its accuracy. The fact that the GMT correlation produces only a few eclipse occurrences on the day-names specified by the Classic Period Mayas in the Dresden Codex Eclipse Table suggests that there are more than a few reasonable questions about its accuracy. In fact, that failure alone of the correlation now favored by most European scholars should render it unacceptable as a means of determining how the Mayas perceived the sky because the interaction between the sun and the moon is a primary cause for the choice of intervals the Mayas used in the creation of their calendrical system in the first place. As I pointed out in the previous note, the difference between the length of the LC notation itself and the day-name sequence of the Calendar Round is exactly equivalent to the length of the Dresden Codex Eclipse Table; that is, 11,960 days. In the GMT correlation, no sense can be made of that fact whatsoever and one must be content to assume that the difference is merely coincidental and nothing more. Using a correlation number of 563334 as I have proposed here, however, the final 4 Ahau 8 Cumku date (9.15.1.8.0) that falls before the Dresden Codex Eclipse Table base-day during the Classic Period marks a lunar eclipse which occurs 11,960 days before a second eclipse which is marked by the 21st position of the Maya Eclipse Table on the day-name 4 Ahau 3 Kankin (9.16.14.12.0), which is the same day-name that terminates the LC, or IS, notational sequence 13 Baktuns after the count began on April 29, 3171 B. C. (Julian Day 563334).

While astronomical data of this kind can be explained in terms of the methodology that was used to fix the zero base-day in its particular place; that is, since an eclipse sequence was found during the broad parameters of the Classic Period which exactly matched the day-name sequence of the Dresden Codex Eclipse Table and the beginning of that sequence of eclipses, as the base-day for the table, was used in retrospect to fix a position 1,414,848 days (9.16.4.10.8) prior to it, which represents the exact location of the zero base-day relative to that base-day, and because the 11,960-day interval is an effective eclipse calculation number, it would be more surprising to find no eclipses in this context than it would be to find them where they are. In other words, it is inevitable that these two eclipses are found on the day-names specified by this structure. What this means is that other evidence must be assembled to demonstrate the possible validity of this correlation number.

That evidence falls readily to hand in the context of the Dresden Codex Venus Table's first day (3 Cib 9 Zac), 236 days after its base-day on 9.9.9.16.0 1 Ahau 18 Kayab (May 21, 566 A.D.--Julian Day #1927930). On that day Venus had reached 0.2* of elongation from the sun in the evening sky and was only a few hours past its superior conjunction with the sun. Twenty days prior to that (May 1, 566 A.D.) Venus reached 5.3* of elongation in the morning sky, as it moved toward solar conjunction, and rose at 5:24 AM. Two minutes before that Alcyone, one of the stars in the Pleiades cluster, crossed the eastern horizon at 5:22 AM. While both the cluster and Venus were invisible at this time because of their proximity to the sun, it is perfectly reasonable to assume that Maya astronomers were aware of the approximate time of their conjunction with each other because we can assume that they had been watching both the cluster and Venus as they approached the sun. Twenty-six days before the Venus Table position at 3 Cib 9 Zac, Venus reached 6.9* of elongation on its last day of visibility in the morning sky before superior conjunction. On that day, April 25, 566 A.D.--Julian Day #1927904, Alcyone rose at 5:46 AM, or three minutes after the sun, which crossed the horizon at 5:43 AM.

To say that a similar astronomy exists at the zero base-day position in this correlation proposal would be the same as understating the case. While the astronomy is not identical, one can see in it an articulation of the regular progression of celestial motion that occurs inevitably through the normal passage of real time. What I mean by that concerns the fact that the zero base-day position at 13.0.0.0.0 4 Ahau 8 Cumku (April 29, 3171 B.C.--Julian Day #563334) marks Venus's position in the evening sky at an elongation of 7.6* of separation from the sun after its superior conjunction. Venus's first day of visibility in the evening sky after superior conjunction probably would have occurred a day or two before this. Twenty-seven days before the zero base-day, on April 2, 3171 B.C., Venus reached 1.0* of elongation from the sun in the evening sky and crossed the eastern horizon after sunrise at 6:17 AM. Five minutes before that, at 6:12 AM, Alcyone and the sun crossed the horizon together in conjunction with each other. What one can see here in the transition from zero base-day to the base-day of the Dresden Codex Venus Table is a sequence of events connecting the star cluster of the Pleiades, the planet Venus, and the sun in an articulation that sets the calendrical system in motion with Venus's first day of visibility after superior conjunction with the sun when the sun was also in conjunction with the Pleiades at the same time. When one then arrives at the first day of the Dresden Codex Venus Table (3 Cib 9 Zac), 3,738 Mayan years and 226 days later, Venus has just reached superior conjunction with the sun after being in conjunction with the Pleiades 6 days after its last day of visibility before superior conjunction and 20 before reaching 3 Cib 9 Zac.

What is most significant here is the fact that the zero base-day was determined, not by any association that might exist in Maya astronomy between Venus's interaction with the Pleiades at or near Vernal Equinox (April 17, 3171 B.C.), but by fixing the base-day of the Dresden Codex Eclipse Table (9.16.4.10.8 12 Lamat 1 Muan) on the day of a lunar eclipse (June 29, 698 A. D.--Julian Day #1976182), which then counts all the relevant eclipses (both lunar and solar) on the day-names specified by the table's articulation of such events, and then counting back in time the specified number of days, 1,412,848, to determine precisely where that zero base-day occurred in the past. Whatever else one might wish to say about this astronomy, it probably cannot be called a coincidence.

The following table displays the pertinent planetary and stellar positions with their associated Julian Day Numbers and Calendar Round day-names:

Julian Day Christian Date Calendar Round Day-Name Associated Astronomy
563306 1-April 3171 2 Eb 0 Kayab Venus 1.0* Msky rise 6:17 AM/ Alcyone rise 6:16 AM/ Sunrise 6:13 AM
563307 2-April 3171 3 Ben 1 Kayab Venus 1.0* Esky rise 6:17 AM (SC)/ Alcyone rise 6:12 AM/ Sunrise 6:12 AM
563319 14-April 3171 2 Chicchan 13 Kayab Venus 3.5* Esky dcl -00*21'00"; Mercury 12.5* Msky rise 5:27 AM/ Alcyone rise 5:25 AM
563320 15-April 3171 3 Cimi 14 Kayab Venus 3.8* Esky dcl +00*10'56"
563322 17-April 3171 5 Lamat 16 Kayab Vernal Equinox
563329 24-April 3171 12 Men 3 Cumku Venus 6.2* Esky; Mercury 0.9* Msky
563330 25-April 3171 13 Cib 4 Cumku Venus 6.5* Esky; Mercury 0.8* Esky (SC); Venus first day visible after SC with Alcyone in Msky altitude 14*57'43" at sunrise (5:48 AM)
563334 29-April 3171 4 Ahau 8 Cumku Venus 7.6* Esky

Another highly significant fact expressed by this sequence of events, from an ethnohistorical point of view, is that this relationship between Venus and the Pleiades occurred at the end of the dry season in the tropical rain forest where the Mayas created their extensive agrarian civilization. The temporal location of 4 Ahau 8 Cumku in this correlation may well signify the final day of planting before the beginning of the rainy season in all of ancient Mesoamerica. Finding a way to fix the zero base-day of the Maya LC notation at this particular point during the tropical year may well have been an ultimate guiding principle behind the effort of Classic Period Maya astronomers to establish the point of departure for their entire calendrical system.


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