The ancient Maya recognized several different interlocking and repeating cycles of time, including a 260 day cycle, known as the Tzolk'in, a 360 day cycle which formed the basis of the Long Count, and the 365 day Haab year. The Haab (or Hab') is made up of eighteen 20 day "months", or winals, and one 5 day period. Through sophisticated astronomical observation, the ancient Maya understood that the solar year was approximately one quarter of a day longer, but the Haab was observed as an unbroken cycle of 365 whole days throughout the Classic Period (200 - 900 CE).

For this reason, the time of year during which each 20 day winal occurred would change over time, drifting at a rate of approximately one day every four years, and one whole winal every eighty-three years. In 754 years, the entire Haab is half a year from where it began, and it returns to its starting seasonal position in 1507 solar years, or 1508 Haab.

The Haab glyphs for each 20 day period remained relatively consistent throughout the Classic period. However, it is not yet known if these glyphs were meant to conform to particular seasons at the time they were first used. Some of these glyphs appear to relate both seasonal and astronomical information, such as directional colors, that may provide further clues to their original seasonal configurations. The Classic period spellings of the Haab glyphs are given in the table below, with their approximate meanings. Below the table, I provide an additional interpretation of these names, based on my current research.

Throughout the Postclassic, the names and dates of the Haab winals drifted and varied among different Maya groups. By the time the Spanish invaded the Yucatan, Friar Diego de Landa, who destroyed nearly all of the Yucatecan Maya books, recorded the Haab calendar in the 1560's as beginning with the first of Pop on the equivalent of July 26 of the Gregorian calendar. This date became fixed, and the Yucatecan winal names, most of which differ from the Classic period names, are the names by which the Haab months are now commonly known. These Yucatecan names are also given below with de Landa's dates.

Glyph	Classic Spelling	Approximate Meaning	Yucatecan Name	Meaning	Month/Day
	K'AN-JAL-wa	K'anjalaw: Yellow Weaving (Moon?)	Pop	Mat	7/26 - 8/14
	IK'-K'AT	Ik' K'at: Black Cross	Wo	Toad	8/15 - 9/3
	CHAK K'AT	Chak K'at: Red Cross	Sip	Deer	9/4 - 9/23
	SUTZ'	Sutz': Bat	Sotz'	Bat	9/24 - 10/13
	ka/ku-se/tze?-wa	Kasew/Kutzew: Turkey? (Moon?)	Tzek	Skull?	10/14 - 11/2
	CHIK-ni	Chikin: Bird	Xul	End	11/3 - 11/22
	YAX-K'IN-ni	Yaxk'in: Green/New Sun	Yaxk'in	Green/New Sun	11/23- 12/12
	mo-lo	Mol: Gather?	Mol	Gather	12/13- 1/1
	IK'-SIHOM?-ma	Ik' Sihom: Black Winter Milpa	Ch'en	Cave/Well	1/2 - 1/21
	YAX-SIHOM?-ma	Yax Sihom: Green Winter Milpa	Yax	Green	1/22 - 2/10
	SAK-SIHOM?-ma	Sak Sihom: White Winter Milpa	Sak	White	2/11 - 3/2
	CHAK-SIHOM?-ma	Chak Sihom: Red Winter Milpa	Keh	Stag	3/3 - 3/22
	ma-ka	Mak: Turtle Shell	Mak	Turtle Shell	3/23 - 4/11
	tzu?/UNIW?-wa	Tzuw: Gourd?; Uniw: Avacado (Moon?)	K'ank'in	Yellow/Ripe Sun	4/12 - 5/1
	MUWAHN-ni	Muwahn: Mythical Bird/Hawk	Muwan	Mythical Bird/Hawk	5/2 - 5/21
	PAS?-HAAB	Pas Haab: Dawn of the Year?	Pax	Drum	5/22 - 6/10
	K'AN-a-si-ya	K'anasiy: Yellow Turtle Firewood?	K'ayab	Song	6/11 - 6/30
	HUL?-OHL-la	Hulohl: Arrive at the Center?	Kumk'u	Vessel God	7/1 - 7/20
	WAY-HAAB	Wayhaab: Transformation of the Year?	Wayeb	Sleeping/Dreaming of the Haab (five day period)	7/21 - 7/25

Astronomical Research on the Haab I became interested in studying the ancient Maya through my interest in cacao. This led to a project in which I sculpted the Haab calendar glyphs for the purposes of casting them into chocolate. In doing so, I became interested in their possible astronomical meanings, which in turn, led to my current research in Maya astronomy. I noticed that some of the Haab glyphs appear to correspond with known astronomical glyphs, such as the crossed bands (T552), which is present in the sequential winals known as Wo and Sip, as well as a recognizable element in iconographic representations of celestial sky-bands. The original names for these winals appear to have been Ik' K'at and Chak K'at, both attested in ethnographic records from Chol speakers. The variable element that appears with the crossed bands glyph in the names of these winals corresponds to the colors IK', 'black', and CHAK, 'red'. These colors are known to correspond to cardinal directions among the Maya, with black representing 'west' and red representing 'east', while several scholars have interpreted the crossed bands as a representation of one of the two sidereal positions of the crossing of the ecliptic with the Milky Way (see Milbrath: "Star Gods of the Maya" 1999). Working with the assumption that the original meanings of the Haab months may have corresponded with seasonal positions, I first reasoned that the winals Ik' K'at and Chak K'at could represent the appearance of one of the celestial crossed bands, first in the west at sunset, then appearing in the east at sunrise in the following winal. Many years later, I now believe that these two names originally referenced the visible sidereal position of the full moon (against the background of stars), first to the west (left) of the Milky Way/ ecliptic in Sagittarius, and then to the east (right) of this same sidereal position in the next winal. Indeed, when the majority of the Haab glyphs first appear in the late Fourth Century CE, we find Ik' K'at occurring when the full moon is to the west of the Milky Way in Sagittarius in mid to late May, which would place the first winal K'anjalaw in early May, perhaps corresponding to the May zenith of the sun at Maya latitudes. Five of the Haab months show w(a) suffixes that (in Pop, Tzek, and Mol) can include or be substituted by a skull, elsewhere read as UH (T1049). I believe these both indicate 'uh', meaning 'moon'. In addition, a full half of the Haab winal names include a color glyph that may indicate a direction, such as Yaxk'in, with YAX as green/center and K'IN as sun, suggesting a solar zenith, when the sun is in the exact center of the sky at noon, which occurs on this winal in the Fifth Century at Maya latitudes. The four winals that include the name Sihom also contain color glyphs that may indicate directions. Sihom refers to the Chol winter maize harvest from November to February in the Lowlands, and this time period again closely corresponds to the dates when these winals occur in the Fourth and Fifth Centuries. The directional colors in this case may also refer to the position of the moon, first to the west of a specific sidereal position in Ik' Sihom, followed by Yax Sihom, which here may refer to the lunar zenith in November, when the moon is in the center of the sky, close to the Pleiades at this time, and opposite it's position in the New Year at Pop. Sak Sihom would then position the moon in its farthest northern position, north of the zenith, while Chak Sihom would place the moon to the east of this zenith position. For these reasons, I believe that the unusual features of the main glyph in these winals, also seen in the day named Kawak, may have originally referred to the sidereal position of the Pleaides and the Hyades in Taurus, the latter of which has a unique, triangular 'billiard balls' arrangement. Within many of the Haab winal names, I have since found multiple correspondences that support my original working hypothesis that the Haab winals originally represented a combination of seasonally specific lunar and solar sidereal positions during the Fourth and Fifth Centuries CE, and I hope to finally publish the results of this study in the near future. - Michael J. Grofe, Ph.D.