The Correlation of Calendars

The existence of the 260-day count in Mesoamerica extends back at least 2,500 years. This count or calendar, as it is generally called, is really a remarkable astrological instrument. It is an arrangement of blocks of time (days and groups of days) that resonate with life on this planet. The Maya call this count the Tzolkin, the Aztecs the Tonalpouhalli. In the computer program "Maya/Aztec Astro-Report," and my books "Day-Signs" and "Signs of Time," I refer to it as the 260-day astrological calendar. It is not connected to the seasons and therefore does not require periodic correction. But in order to know when a particular day arrives, we must have a method of correlating it with a seasonal calendar.

One way of correlating the 260-day astrological calendar with the civil calendar is to link it to a Julian date. Historians and astronomers have the days numbered, as far back as several millennia before the Common Era. If we know the Julian date of an event, and we have our calendars linked to this system, then we can move dates back and forth between calendars. Nearly all researchers now agree that the Maya inscriptions show that the zero date of the Long Count (a.k.a. the Mayan Calendar) began on Julian date #584,283 which is August 11, 3114 B.C.E. This correlation has come to be known as the Goodman-Martinez-Thompson correlation (GMT). These three respected researchers struggled with this problem for much of the 20th century eventually reaching a consensus. According to the GMT correlation, the day 4-Ahau, or 4-Flower occurred on that date. Once we have a Julian day correlation we can easily bring the 260-day astrological calendar into modern times.

The consistency of the Maya inscriptions indicates that the 260-day count was not tampered with. Other calendars were changed, but the count, much like the 7-day week in the West, never skipped a beat. During the Spanish Invasion of Mesoamerica a few writers noted specific dates in the Western calendar and in the native 260-day count. When these are compared with the GMT they check out perfectly. Ethnologists studying the Quiche Maya in Guatemala have found that the 260-day count used today matches the GMT perfectly also. In other words, the archaeologists, archaeoastronomers, historians, and present-day Quiche Maya all agree on the correlation between the Western calendar and the 260-day astrological calendar, the correlation called the GMT.

Several other correlations have been proposed. In Linda Schele's books a correlation proposed by Floyd Loundsbury that differs from the generally accepted GMT by 2 days is used. Some readers in Mexico use correlations that vary widely from the GMT. Jose Arguelles and the followers of his product "Dreamspell" use a correlation that ignores leap year and thus loses one day every four years. Between 1992 and 1996 it differed from the GMT by 52 days. Between 1996 and 2000 it will differ by 51 days. In the opinion of this writer, the GMT works better than the others for astrological purposes.

In conclusion, differences in calendar correlation can be compared to the differences between advocates of the Tropical zodiac and the Sidereal zodiac. The vast majority of Western astrologers locate the beginning of the zodiac (the first degree of Aries) at the vernal equinox. A small minority of Western astrologers, who call themselves Siderealists and mostly specialize in prediction, begin the zodiac about 26 degrees before this point. They take into account what is called precession, the slow shift of the vernal equinox against the stars. The majority of Hindu astrologers also use one version or other of the Sidereal zodiac. In fact, the government of India has an official ayanamsa or distance between the vernal point and the beginning of the zodiac. Hindu astrology is generally known for its predictive powers, not for its psychological analysis. The real question though is "what works best?" It appears that the vast majority of astrologers who interpret the influence of the zodiac in a psychological way work with the Tropical zodiac. Also, most forecasting techniques in astrology don't really require a zodiac, any kind of background grid will suffice for the most part. Go figure. Since there is no funding for scientific studies in astrology, we will each have to sort out these kinds of issues, i.e. calendar correlations or zodiacs, for ourselves -- or let some authority we happen to trust do it for us.

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