Arawak astronomers

Further research in Antigua suggests that the stones on Greencastle Hill really may have been used by Arawaks a thousand years ago to track time and season

  • Photograph by Maura Imbert
  • The author's survey in progress on Greencastle Hill. Photograph by Maura Imbert
  • The author's survey in progress on Greencastle Hill. The three sacred peaks can be clearly seen. Photograph by Maura Imbert
  • Photograph by Maura Imbert
  • Part of the Trinidad campus of the University of the West Indies. Photograph by Maura Imbert

The possibility that Greencastle Hill in Antigua may be a “tropical Stonehenge” dating back to the Caribbean’s indigenous, pre-Columbian peoples was discussed in the January-February 2001 issue of Caribbean Beat.

Greencastle Hill rises to over 200 metres; it is the core of an isolated volcano in which rhomboidal and polygonal columns of rock formed. Erosion then produced a plateau strewn with boulders of many shapes and sizes, and it is here that some researchers believe that religious ceremonies and astronomical determinations were carried out.

This theory is based on stone circles associated with what are considered to be “megaliths” among the rock columns which, to some researchers, appear to have been arranged by man. Definite clusters of “megaliths” still exist on the hill; the largest and most prominent have been described as “male phallic and female generative symbols” by Al Hajji Talib Ahmad Dawud, who delivered a paper entitled The Megalithic Monuments of Greencastle Hill at the Fourth International Congress for the Study of Pre-Columbian Cultures of the Lesser Antilles in 1973.

Megalithic sites have been found in many parts of the world, the most famous being Stonehenge in southern England. Many are now being investigated to determine whether they had any astronomical significance. Among other things, researchers compare the bearings of the stone features on a site with the rising and setting points of significant celestial objects. A star rising just before sunrise or setting just after sunset (the star’s “heliacal rising and setting”) were considered to be important in the keeping of prehistoric calendars.

Greencastle Hill was occupied by pre-Columbian Arawak people during the Ceramic Age (ca. 1000–1250 AD). No previous investigation of their astronomy has been reported, so the author and Arleene Atwell, a student of the Department of Land Surveying and Information at the Trinidad campus of the University of the West Indies, carried out a preliminary survey of 18 megaliths on the hill, including the prominent “phallic and female” symbols mentioned by Dawud.

The bearings of these stones were compared with the azimuths of stars known to be important to Arawak cultures. (The azimuth is the direction to a star along the horizon, measured in degrees from the north. A star due east has an azimuth of 90°.) Stellar azimuths for the year 1000 AD were obtained from an astronomical computer programme, and the bearings of the selected stones were determined by theodolite readings from each end of an east-west baseline oriented by solar observations.

The late Ludovick Mann, once the eminent chairman of the Glasgow Archaeological Society, considered the Greencastle Hill megaliths to be “Calendar Stones” — a prehistoric outlay for the purpose of recording time; one of the main objects of our survey was to determine whether this hypothesis could be substantiated.

Many ancient cultures marked the beginning of their year, and the onset of the seasons, by the stars, which were woven into a rich tapestry of mythology. It is now realised that ancient Arawak and Carib cultures possessed considerable astronomical knowledge, which is currently being recorded; this information was used in choosing the particular stars and stellar groups to be investigated.

Stellar azimuths for the year 1000 AD, determined at the rising and setting times of selected stars, were checked with the bearings of the 18 stones to see if matches occurred within a tolerance of plus or minus three degrees. (This tolerance was chosen to account for uncertainties associated with the Arawak method of sighting celestial objects, and errors associated with reading azimuths from computer-generated star maps.)

The first 12 of the 18 stones investigated, when sighted from the first stone, lay, with minor deviations, along a line tilted by about 15 degrees to the true east-west line determined by solar sights. It was possible to see stone 1, the “male symbol”, by looking eastward through the V formed by the two stones of the “female symbol”, stones 8 and 9. Conversely, it was possible to see a range of three-peaked hills (called zemis and sacred to the Arawaks) from stone 1 by looking westward through the V to the distant landscape.

Stone 13 was a peripheral boulder on a circle of stones to the base of the main linear orientation of stones; the results obtained during this investigation indicated that it may have been used as a “sighting stone” in the alignment of stars with the main boulders. Stone 1 also appeared to have been used in sightings.

Some significant correlations were found, include the azimuth of the Pleiades (or Seven Sisters) at their heliacal rising around May 3 and the bearings of the “female symbol” stones, 8 and 9, when sighted from stone 13. The heliacal rising of the Pleiades signified the start of the new year to the Arawaks and the time to begin preparing the land for planting before the onset of the rainy season. Similar correlations were found between the azimuth of the Pleiades on June 16 (the date of the Summer Solstice in 1000 AD) and stones 1, 2, 3, 4, 5, 6 and 7.

Ursa Major (The Plough) was another important constellation in Arawak mythology, since its rising indicated the start of the hurricane season. The azimuth of the bright “pointer star”, Dubhe, was chosen for azimuth determinations, since this star would appear first above the horizon. In the Caribbean region, the hurricane season traditionally runs from June to October, and Ursa Major straddles the meridian at sunset at the Summer Solstice. The heliacal rising of Ursa Major was found to occur at the beginning of August from the computerised star maps; this rising marked the most dangerous months of the hurricane season, when navigation was hazardous. The azimuth readings for Dubhe, however, during August and September did not coincide with the bearings of any of the 18 investigated stones, although the azimuth of the rising Sun during this period coincided with the bearings of stones 8 and 9, the “female symbol”.

Other important azimuth/bearing correlations include those for Betelgeuse, the red giant star in the constellation Orion; Procyon, the brightest star in the small constellation Canis Minor; and Aldebaran in the stellar group the Hyades, which outlines the head of Taurus.

Further south, in the Guianas, the heliacal setting of Orion at the June Solstice was used to mark the onset of the dry season, but in Antigua, where the heliacal setting occurred on June 1 in 1000 AD, it would have heralded the onset of the rainy season. The use of certain constellations and their bright stars as “calendar stars” may have been retained by Arawaks who sailed north to the Lesser Antilles. Orion was definitely involved in the “ordering of the seasons”.

Procyon, in Canis Minor, was associated with hurricanes by both the Arawaks and the Caribs, and correlations between its azimuths and several of the chosen stones were found at both the equinoxes and the solstices.

It can be seen from the results of this preliminary survey of the “megaliths” of Greencastle Hill that correlations have been found between their bearings and the azimuths of stars important in Arawak mythology. Some of these correlations may be spurious, but their number suggests that Arawak people occupying Greencastle Hill in 1000 AD may well have used the site as an astronomical observatory. It is highly unlikely that the V-shape of the “female symbols” and the non-aligned stones of the “male symbol” were natural features.

The Greencastle Hill site is a rich source of information for the archaeoastronomer, and its position and elevation make it an ideal spot for the study of time-keeping related to the stars.


Bearings Between Significant “Megaliths” And Stellar Azimuths At Stellar Risings And Settings

Sighting from Stone 13: Star Risings

Stones Bearing Star(s) Azimuths Date
1 89.9° Pleiades 87.12° June 16 (Summer Solstice)
2 88.2° Betelgeuse 91.9° Dec. 15 (Winter Solstice)
3 86.1° Procyon 86.5° Dec. 15 (Winter Solstice)
4 86.9° Procyon 87.5° Sept. 17 (Fall Equinox)
5 86.7° Procyon 86.5° Dec. 13 (Winter Solstice)
6 85.6° Aldebaran 84.1° Dec. 13 (Winter Solstice)
7 89.9° Betelgeuse 90.4° Sept. 17 (Fall Equinox)
8 82.6° Aldebaran 83.8° Dec. 13 (Winter Solstice)
May 3
(Start of Arawak Year;
Heliacal Rising of Pleiades)
10 68.8° N/A
11 69.4° N/A
12 19.6° N/A


Sightings from Stone 1: Star Settings

Stones Bearing Star(s) Azimuths Date


March 14
March 14
June 1
(Spring Equinox)
(Spring Equinox)
(Heliacal Setting)
June 16
(Summer Solstice;
Heliacal Setting)
4 282.1° Procyon 281.2° March 14 (Spring Equinox)
5 282.8° Procyon 282.5° June 16 (Summer Solstice)
6 283.4° Procyon 282.5° June 16 (Heliacal Setting)
7 270.2° No correlation
8 283.5° Procyon 282.5° June 16 (Heliacal Setting)
9 284.8° Aldebaran 284.2° Dec. 13 (Winter Solstice)
10 288.9° Pleiades 291.0° May 3 (Start of Arawak Year)
11 288.1° Pleiades 290.7° March 14 (Spring Equinox)
12 285.7° Aldebaran 285.1° March 14 (Spring Equinox)



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