Tenabo, New Mexico

Possible Archaeoastronomical Implications

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An examination of the possible astronomical significance of the site of Tenabo, New Mexico, to the indigenous Puebloan Indian cultures that inhabited the area approximately 500 to 1000 years b.p.e. The on-site survey was conducted on April 18, 1988. Site work and subsequent analysis was carried out by the following members of the Lake County (Illinois) Astronomical Society:

Grant Barlow
Jack Kramer
Greg Lutes
Tom Mathieson
George Murphy
Bill Otten
Michael Purcell
Gary Smith

The study was undertaken with the assistance of Messrs. Glenn Fulfer and Tom Carroll of the National Park Service. We extend our appreciation to them.


Abstract

Bearings were taken between the stone features at the site of Tenabo and were compared with rising and setting points of significant celestial objects. A number of positive correlations were found with the bearings of sunrise, sunset, bright stars, the Pleiades, Orion’s Belt, lunar standstills, the Crab Nebula (site of the supernova of 1054). A nearby star and crescent petroglyph was also found; this matches other such glyphs in the American southwest that have been suggested as representing the Supernova of 1054.

The following report was written by Jack Kramer, August 1988.

Introduction

To the ancient Indian cultures of New Mexico’s Salinas area, the consistent rising and setting of the Sun, Moon, and stars must have pointed to a certain orderliness in the universe. Since they had adopted some amount of agriculture, it’s logical that in their minds the movements of these heavenly lights would have related to the growing season and their dependence on the Sun and the weather it brought them.

Tenabo may have been a place where a select member of the tribe watched the sky at dawn and dusk and, in effect, created a useful agricultural calendar. This person may have determined that the Sun rises in an extreme northerly position at the time of the year when the weather is at its most clement. If so, he probably also noted that when the Sun rises at its most southerly point, the worst of the winter is still ahead.

Of course, we can never know with certainty whether Tenabo was just such a place. There has been found no written or pictorial record to substantiate this. We realize that there is a danger of imposing our twentieth century knowledge of the universe on peoples of long-past ages and reading into rock placements a significance that was never intended. On-site analysis showed that the rock features at Tenabo do give an indication of having been erected by human hands. Why they were erected may never be known with certainty, and although we are presenting some possibilities, it’s essential to maintain a certain amount of healthy skepticism.

In mid-1987, Superintendent Thomas B. Carroll of the National Park Service at Salinas National Monument informed the Lake County Astronomical Society of two sites which give evidence that manmade structures there align with rising and setting points of celestial objects. One of these sites was Wizard’s Roost and the other was Tenabo. Since the latter site is more accessible, LCAS opted to concentrate the initial effort there. The opportunity to apply our knowledge of astronomy to determine the significance of this site enkindled a great deal of enthusiasm. On April 18, 1988, eleven members of the Society converged on Tenabo.

It should be noted that the LCAS members are amateur astronomers; those who conducted the site work and analysis have some training in astronomy, surveying, and anthropology, but no formal credentials in archaeoastronomy. The references shown in the attached bibliography provided much valuable background information, as did some conversations with practicing archaeoastronomers.

 

Site Description

The site of Tenabo is virtually devoid of vegetation. The soil is sandy and includes a high percentage of small stone fragments which appear to be crushed shale. The underlying rock is visible in various places at the surface, but protrudes only an inch or two above the ground level.

Four of the features are horseshoe-shaped, composed of a single-tier of rocks laying on the surface. For identification purposes, we named these the "north", "south", "deep south", and "west" features. Their size varies between four and six feet in width.

The acquisition of azimuth bearings between the various features at Tenabo had to be accomplished under certain assumptions. If the Indians did use these features for astronomical purposes, we aren’t sure exactly how they were used. In other words, they might have used poles set in the middle of the features to cast shadows of the rising and setting Sun. An alternative would have been to sit or stand within the features and thereby view any alignments. Because of the orientation and size of the horseshoe-shaped features we believe it’s likely that an observer would be positioned within the features, probably in a seated position. Accordingly, we took the azimuth bearings from the approximate center of each feature.

The feature designated as the "north four rocks" is partially covered by a juniper tree. This feature appears on a map of the site given to us by Tom Carroll; the map is of unknown origin. We questioned whether this is a manmade feature or natural happenstance. We did take bearings through the center of these rocks, and further consideration suggests that they may have supported a staff which acted as a gnomon to cast a shadow of the rising Sun or more precisely indicate a rising point against the hills in the background. Later analysis of the bearings disclosed that this "north four rocks" feature, along with the "west" feature, produces one of the closest alignments to indicate the sunrise of the summer solstice.

The "central" and "east" features are single tiers of rocks in roughly circular patterns. The central feature is fairly complete, while the east feature is missing a number of rocks. Both of these are substantially larger in diameter than the other features. Bearings were taken from the center of these features. The central feature is not perfectly circular, being roughly 19 ft. by 21 ft. There may have been some other purpose for the central and east features, but lacking any evidence of an alternative use, we considered them as part of the overall astronomical alignment scheme.

The appearance of all the features creates some assumptions about their logical use. Any description of the features must take into account the fact that they may not appear as originally constructed. For one thing, this is range land; cow dung and hoofprints testify to the presence of cattle, which could have kicked the smaller stones out of their original configurations.

The major features are located on a fairly level plateau considerably above the surrounding land. The east and deep south features are at a somewhat lower position on ground that slopes away from the top of the plateau. For all practical purposes, we regarded the top of the plateau as being perfectly horizontal. The true horizon on the east, south, and west is obscured by hills. Since this would have some influence on the azimuth of any rising or setting celestial object, we used the transit to take elevations of the horizons through the various features. The elevations above the horizontal plane for lines between different features are as follows:

central to north
west to north
central to west1°15’
central to south2°45’
central to deep south2°55’
central to east3°15’
west to north four rocks1°50’

Some features shown on the earlier map of the site are identified as "sandstone discs". Upon examination, we concluded that these "discs" are outcroppings of underlying rock, with no particular significance for our purposes here. There are several such outcroppings at the site, and they do not appear to be sandstone, but rather, the gray color suggests a type of limestone. We have somewhat altered this earlier map of unknown origin, based on our findings; a copy is included with this report. We have added one feature not originally included; this is the one we’ve designated as "deep south". It’s a horseshoe-shaped grouping of rocks located below the top level of the plateau. The shape is not as well defined as in the other "horseshoe" groupings, but we felt there is a possibility that this is more than just a random distribution of rocks. We opted to investigate whether there could be some significance to this feature.

Site

Surveying Methods and Derivation of Azimuths

In the comparison of bearings between features with the azimuths of sunrises, sunsets, and risings of stars, a question of tolerance arises. In other words, it becomes a question of whether a significant alignment has been identified even though our bearing between features deviates from the actual azimuth of a celestial body by a certain amount. Our decision was that a deviation of two degrees or less between the azimuths could be considered as a positive correlation. This takes into account the assumptions and circumstances of the site mentioned previously. As an example, the bearing we found from the west to south feature is 121°07’. The azimuth of sunrise on December 21 was found to be 119°24’, using a computer simulation of the Tenabo sky in the year 1100 A.D. We consider that these two azimuths show a corresponding agreement.

Upon arriving at the site, we determined the direction of true north via a Sun line at solar noon. The longitude of Tenabo is about 106°30’, which is a little over one degree west of the time zone central meridian. This equated to roughly four minutes past local noon. Since we were on Mountain Daylight Savings Time, solar noon occurred at 1:04 P.M. The shadow cast by a plumb bob suspended from the transit tripod provided a reasonably accurate direction of true north. This was then used to set up a grid system whereby true north could be determined from any point at which a bearing was being taken.

Using the transit, we took bearings between the approximate center points of the features. The linear distances between these points were also measured. An accompanying table lists the bearings.

During the ensuing weeks, a computer program was used to generate a pictorial representation of the sky on various dates. This allowed us to define the azimuth of the rising and setting Sun, Moon, and certain bright stars. The azimuth was taken for that point where the upper limb of the Sun would be just above the actual horizon. The computer simulation takes into account precession, which is important for the stars, but inconsequential for Solar System objects. The year selected for the analyses was 1100 A.D. -- a possible date for the earliest occupation of the site, based partly on the recovery of Chupadero black-on-white pottery at Tenabo and generally-accepted dates of habitation in the area.

Normally, heliacal star risings are considered to be important for calendar-keeping functions. The heliacal rising and setting of a bright star depends on the date that the star is first seen in the sky rising just before the Sun or the last time it’s seen after sunset. This presupposes certain ground rules for the star’s visibility at these points. In actual practice, this could be affected by how keen-eyed the observer may have been. Since the date that the Indians might have wanted to identify by a heliacal alignment would be unknown to us, we didn’t concern ourselves with the heliacal issue. Instead, we sought to determine whether any features aligned with star rising points.

Once the computer program identified a solar or stellar azimuth, we checked the bearings between the features to see if there was a match, with a tolerance of plus or minus two degrees. With regard to sunrises and sunsets, we checked the solstices and equinoxes. Certainly, other dates also may have been significant to the Indians for ceremonial or agricultural purposes, so we can’t be assured that all possibilities have been considered.


Bearings Between Features at Tenabo

The table below contains a listing of all the bearings we had taken in our survey of the site.

FeaturesBearingFeatures Bearing
Central to: North to:
north 347°35’central167°35’
west 284°55’west227°30’
south 149°05’south160°32’
deep south144°10’deep south154°43’
east 112°35’ east 133°16’
north four 15°30’north four 91°40’
West to:South to:
central104°55’central 329°05’
north 47°30’ north340°32’
south 121°07’ west301°07’
deep south126°10’deep south139°10’
east109°34’east 94°09’
north four 61°17’north four358°05’
Deep South to:East to:
central324°10’central 292°35’
north 334°43’ north313°16’
west 306°10’ west289°34’
south 319°10’ south274°09’
east 63°51’deep south243°51’
north four347°07’north four 322°32’
North Four to:
central195°30’
north 271°40’
west 241°17’
south 178°05’
deep south167°07’
east 142°32’

Sunrise and Sunset Alignments

The following table identifies the most likely feature alignments with the azimuths of the Sun as it rose or set with respect to the actual horizon at Tenabo.

DateSolar Azimuth Closest Feature Bearing
June 21 rise61°19’61°17’ west to north four
June 21 set300°38’301°07’ south to west
December 21 rise119°24’121°07’ west to south
December 21 set242°08’241°17’ north four to west
March 21 rise 87°02’ 91°40’ north to north four
March 21 set274°22’ 274°09’ east to south
September 23 rise 93°04’94°09’ south to east
September 23 set267°01’271°40’ north four to north

In the case of the March 21 sunrise and September 23 sunset, it’s difficult to conclude that a positive correlation exists. On the other hand, the sunrises and sunsets on the remaining dates do seem to have feature bearings that align reasonably well.

Most of the features that correlate positively are located at the top of the plateau; these are the north, north four rocks, south, and west features. The only exception is the east feature, which is included in two positive alignments, both involving equinox points. This causes us to wonder why the east feature wasn’t erected on the same level as the other features, even though it might have been an addition made in later years. In both cases where the east feature is involved in an alignment, its partner is the south feature, each of which is visible from the other. But it would have been an easy task to erect one or more features like the north four rocks on the "upper" level in order to accomplish the alignments which now involve the east feature. This calls into question the intended purpose of the east feature. Is the solar alignment merely coincidental? Was there some reason why the Indians didn’t want the east feature to be on the same level as the other features? We’ll never know.

Possible Lunar Alignments

Reference material indicates that the Moon was of considerable interest to the Indians of the Southwest. There’s certainly a possibility that it entered into their calendar reckoning. We felt that the study of Tenabo would be incomplete unless we investigated any potential feature alignments with the Moon.

We decided to consider a cyclical characteristic that probably would have been noted by the Indians. This is the fact that the Moon doesn't always rise and set at the same point on the horizon. A check of the extreme northerly and southerly moonrises, or stand-still points, indicated that the Moon should rise at its extreme south position at an azimuth of about 149°; this correlates very well with the bearing of 149°05’ from the central to the south feature. The most northerly moonrise occurs at about 31°30’, but there is no feature bearing close to this. There is no feature bearing close to the southernmost moonset. However, the most northern moonset of 329° agrees well with the bearing of 329°05’ from the south to the central feature.

There is an issue presented by the lunar alignments. We wonder whether they’re pure happenstance, rather than a conscious effort on the part of the Indians. Why would the Indians mark the most southerly moonrise, while apparently ignoring its counterpart -- the northernmost moonrise? If they did somehow mark the northernmost moonrise, we have found no indication of it. We aren’t prepared to answer this objection here. Nonetheless, there are two very close reciprocal alignments, involving the same two features. There is the possibility of an intentional alignment here.

Star-Rise Alignments

The literature seems to point to the fact that it was only the risings of stars that were of interest to the Indians. Therefore, we opted to concern ourselves only with the azimuths at which various bright stars rise over the actual horizon. We checked the ten brightest stars visible from this site. The following are the stellar azimuths derived, rounded to the nearest 30’.

StarAzimuthClosest Feature Bearings
Sirius111°30’ 112°35’ central to east
Arcturus 62°00’61°17’ west to north four
Vega 43°30’ none
Capella 36°00’none
Rigel103°30’ 104°55’ west to central
Procyon 84°00’none
Betelgeuse 84°00’none
Altair 83°00’none
Aldebaran 74°00’none
Antares121°00’121°07’ west to south

Of the four positive alignments, perhaps the most interesting is that involving Antares, a star that seems to have held special significance for the Indians (per Williamson: Living the Sky). Ethnographic studies disclose that Antares is called the "Coyote Star" by Indians of the Southwest. The azimuth of Antares is quite close to that of sunrise on December 21; obviously, the same two features at Tenabo are involved in both alignments. We might well conclude that this coincidence of nature did not escape the notice of the Indians.

In recognition that the Pleiades is among those objects holding special importance for the Indians, we derived an azimuth for this asterism. We took the azimuth of the first Pleiad to clear the horizon; this was about 64°55’. The closest feature bearing is 63°51’, from the deep south to the east feature. The agreement between these bearings seems close enough to allow the possibility of an intentional alignment.

Using the computer simulation, we checked the bearings for the belt stars of Orion, which are referred-to in Indian lore as a "spear" that rises vertically on the horizon. Moving west to east, we derived the following bearings: Delta Orionis - 93°47’, Epsilon - 94°44’, Zeta - 95°21’. The most nearly aligned bearing is from the south feature to the east feature - 94°09’. This is another positive correlation indicating that the Indians may have also marked the rising of Orion’s Belt - the "Spear" - from Tenabo.

In addition to the above, we derived an azimuth for the Crab Nebula (M1), which is a remnant of the supernova that was seen on July 5, 1054 A.D. This bright star would be a powerful symbol that the indigenous people might wish to commemorate. As a matter of pure speculation, the Indians may have believed that this bright star might one day reappear, and by marking its azimuth, they would know where to look for it. The bearing we derived is 65°30’; the closest feature alignment is 63°51’ from the deep south through the east feature. This difference of less than two degrees is a fairly close correlation. This alignment could have been intentional, especially in view of the fact that some archaeoastronomers have identified petroglyphs throughout the Southwest that suggest the indigenous people did observe and record the Supernova of 1054. This would also help to date the site of Tenabo.

Finally, a computer program was written to check the star-feature alignments over a span of several centuries (600 A.D. to 2000 A.D.) to determine whether there was a tendency toward a higher correlation in a particular century. The thought was that this might help to date the usage of the site. However, the results of this effort were inconclusive.

The Supernova of 1054 Recorded in Stone?

One of our interests was to view the crescent and star petroglyph at Abo. This was referred-to in chapter four of the book In Search of Ancient Astronomies, edited by E. C. Krupp. A drawing in that book shows the crescent and star as it appears at Abo and posits that this might be an indication that the Indians of the Southwest had noted the Supernova of 1054 A.D. which ultimately gave rise to the Crab Nebula. One problem with this particular glyph is that it represents the "supernova" at an incorrect position with respect to the Moon. Moreover, the crescent Moon is shown rotated almost 180° from its actual position; the lunar cusps should be pointing up (in a westerly direction), not downward. But it’s apparent from similar representations elsewhere that the Indians were not overly concerned with the exact positioning of celestial bodies. Of course, this assumes that the numerous crescent and star renderings were actually intended to depict the supernova event. There is some disagreement about this among professionals.

It came as something of a surprise to find another depiction of the crescent and star within walking distance from the Tenabo site. Prior to our visit, we had not seen any reference to this petroglyph in the literature. The star is shown in the correct position with respect to the Moon; however, the Moon is oriented with the cusps downward, rather than in the astronomically-correct upward position. In addition, there are rays shown emanating upward from the star. This could have been meant to indicate that it was an especially bright object. Other possibilities are that the rays were added at a later date or that it’s meant to represent a comet with a tail. An alternative explanation is that it’s not a depiction of a celestial event, but is yet another symbol of the morning star cult, which also appears in petroglyphs throughout the area.

Nova

The glyph is located in a grotto overlooking a dry wash. This would have been an ideal spot from which hunters could await the arrival of game searching for water in the gully. From this vantage point, there is a view to the east from which the Indians could have seen a rising Moon and supernova. Along with the crescent and star, there are pictographs of kachina dancers, plus an abundance of other petroglyphs of unknown age. These other glyphs depict objects such as mountains, clouds, snakes, birds, and human hands. Also shown are mythical beings such as Kokopeli, the hump-backed, flute-playing god of fertility, and a horned ruminant that might be a normal deer or antelope, except for pronounced claws on its feet. The pictograph of a human hand in a prominent spot implies that this grotto had a spiritual significance for those who frequented it.

Subsequently, on April 21, we viewed pictographs near Abo, and there saw the crescent and star glyph as represented in the Krupp book. Thus, within a distance of only a few miles, there exist two representations of the same theme.

Assuming that the crescent and star petroglyphs represent celestial phenomena, it’s interesting to speculate whether the Indians sought to represent a special event or any close conjunction of the Moon and bright star or planet. Coincidentally, on April 19, there was a close conjunction of the Moon and Venus, which we all observed from Gran Quivira National Monument. If we found it so noteworthy, then a similar conjunction may well have inspired the indigenous peoples to represent this in a petroglyph. This could explain the diversity of positions of the star with respect to the crescent Moon in the various renderings. A bright planet, such as Venus, could at various conjunctions assume different positions with respect to the Moon. If the cusps downward attitude of the Moon were to represent physical reality, then the Moon would have to be seen beneath the Sun, after sunrise or before sunset. This would be extremely difficult, to say the least. Moreover, it precludes the supernova event, which had a Moon-star juxtaposition on only one day, immediately before sunrise.

It’s tempting to conclude that the Indians had taken note of the Supernova of 1054 and had recorded this event on the stones of Abo and Tenabo. The literature indicates that this is within the realm of possibility, based on dates of habitation in the area. But there’s no way of proving this hypothesis. Just as we took special note of the Moon-Venus conjunction of April 19, 1988, the Indians may just as well have recorded other conjunctions in their own times. In effect, had the Indians recorded an event (the supernova) or an occurrence (any conjunction)? Moreover, this could just as well be a cult symbol, rather than the depiction of an actual celestial pairing. The stones are silent on this point.

Conclusions

We undertook this project with open minds, tempered with some skepticism. It came as a surprise that so many of the feature bearings correlate relatively well with the azimuths of different celestial bodies. Beyond what we’ve found, there are other aspects of this site that should be explored further. One of these is a grouping of rocks located on the lower eastern slope which have "cut reliefs" that appear as wedges removed from one corner of each rock. We had not taken any bearings involving these rocks. Immediately to the south-southwest, there’s a hill overlooking the site. While this would have been an excellent observing position, our cursory examination revealed nothing to indicate that it was used as such. The site does warrant further analysis; it would be comforting to have professional confirmation of our findings.

Our method was to take the bearings between features without any preconceived notion of their significance. It was only later after we had returned home that we identified correlations between the bearings and the azimuths of celestial objects. The intent was to ensure that we did not skew the results based on any preconceived notions of how the site was used. Through all this, there’s a great deal of conjecture, because we’ll never know the true intentions of those who dwelled here many centuries ago. Nonetheless, we feel secure in drawing two conclusions.

First, it’s apparent that the Puebloan Indians of the area were cognizant of celestial happenings. The nearby petroglyphs testify that they did attempt to record celestial objects. It remains arguable whether this includes the Supernova of 1054 A.D.

The second conclusion is that positive correlations do exist in the alignments of six of the eight sunrise/sunset positions, four of the brightest stars, the Pleiades, the belt stars of Orion, the Supernova of 1054, and two moonrise/moonset positions. While some of the correlations may be dismissed as spurious, the large number of correlations suggests that the indigenous people could have used Tenabo as an astronomical observatory. We feel it is unlikely that these are all purely chance alignments.

Among the unanswered questions, we wonder whether those who crafted the nearby petroglyphs were of the same group as those who erected and/or used the features at Tenabo. Have we identified all the manmade features at Tenabo? What were the dates when this site was used? We had found a large number of pottery shards laying on the ground or partially buried; analysis of these may prove valuable in dating the site.

Tenabo is fertile ground for the archaeoastronomer. It’s an ideal spot from which to observe the sky and keep track of cosmic time via the Sun, Moon and stars. While this site may have been put to a variety of uses, we feel that watching the sky was most probably one of them.

Bibliography

Eddy, John A.
1978 Archaeoastronomy of North America: Cliffs, Mounds, and Medicine Wheels; from the book In Search of Ancient Astronomies, edited by E. C. Krupp; McGraw-Hill.

Salinas
1982 Exploration - Annual Bulletin of the School of American Research, Santa Fe, NM.

Tainter, Joseph A. and Levine, Frances
1987 Cultural Resources Overview - Central New Mexico; USFS and BLM, Albuquerque and Santa Fe, NM.

Williamson, Ray A.
1984 Living the Sky - The Cosmos of the American Indian; University of Oklahoma Press, Norman, OK.

Wimberly, Mark and Eidenbach, Peter
1977 Inventory of the Cultural Resources: Sierra Blanca Ski Area Land Transfer; Human Systems Research, Tularosa, NM. (Prepared for the Bureau of Indian Affairs, Albuquerque, NM.)


Computer Program Used for Derivation of Celestial Azimuths

Sky Travel - 1984, Commodore Business Machines, Inc. & Deltron, Ltd.

It has been assumed that the azimuths of the celestial objects as presented by Sky Travel are essentially accurate. At the time of our research, this was the only program available to us that allowed derivation of the azimuths for the era in question and in the way we needed to view them.

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