Archaeoastronomy

The sun rising over Stonehenge at the 2005 Summer Solstice.

The rising sun illuminates the inner chamber of Newgrange, Ireland, on winter solstice and a week either side, sky conditions permitting.

west side of El Castillo at Chichén Itzá, Mexico

The Great Pyramid of Giza (a.k.a. Kheops or Khufu) near Cairo, Egypt, constructed ~2570 BC, world's tallest building until 1300 AD

Charles Piazzi Smyth(1819-1900)professor of astronomy, University of Edinburgh and Astronomer Royal of Scotland from 1845 to 1888

illustration from Piazzi Smyth's book Our Inheritance in the Great Pyramid with claims of prophetic measurements therein

Richard Anthony Proctor(1837-1888)British astronomer, prolific author, international lecturer

Joseph Lockyer(1836-1920)British astronomer, founded science journal Nature in 1869

Template:FixHTML Archaeoastronomy (also spelled archeoastronomy) is a scientific field seeking to better understand the lives of people in the past through their megalithic, petroglyphic and other ancient memorials constructed, in whole or in part, to honor celestial events. Usually the objective was to note the sun's position on equinoxes, a solstice or other seasonal cusp or annual ritual. Some archaeoastronomical sites or devices were devised as markers for the more extreme limits of the moon's swing in its Metonic cycle. Others may have dealt with rhythms in the motion of planets, stars or entire constellations. Rarely, some sites or devices may have memorialized eclipses, or comets observed on their way toward or away from the heart of the solar system, or supernovae far beyond.

As opposed to modern astronomy, which uses high-technology, radio and optical telescopes to examine space, archaic astronomy was crude, even arcane by design so that only the powerful or literate or priestly understood the mechanics. This can complicate decryption of hidden meanings behind some archaeoastronomical sites or devices as well. Localized cultural context provided by archaeology and anthropology is often essential to interpret what might otherwise remain a mystery. Likewise, historical astronomy provides a wealth of data on when eclipses, lunar standstills and planetary occultations, transits of Venus, comets and supernovae appeared and how the precession of the equinoxes changed the regularity of the skies over the ages. Science wants to know who cared enough to design the markers, what beliefs motivated the designers' interest, where in the world this curiosity arose, why bother with a memorial, when was it built and how followers practiced their observations. Ideally, by investigating archaeoastronomy worldwide, a picture of the intellects, myths, rituals and psychologies of our human forebears may become clearer.

Archaeoastronomers must apply scientific rigor in determining whether observed solar alignments, for example, meet criteria for intentionality. The undisciplined mind can fall victim to delusion, however some imagination is useful in grasping how people of the past might have recognized the complexities of time and marked their lives in ways different from ours. Ancient cultures throughout the world regulated their assorted, primitive calendars by carefully watching the skies, constructing gnomons and targets, and noting patterns of repetition as the years ticked by. Three examples of archaeoastronomy-in-action, solstice sunrises in summer at Stonehenge, in winter at Ireland's Newgrange and equinoxes at the Mayan El Castillo at Chichén Itzá, Mexico, have become famous, attracting the scientifically-inclined as well as general tourists. Even seemingly insignificant sites preserved in the wilderness or behind protective barriers can inspire and inform us about those who came before, where some visitors who neither colonized nor conquered their hosts may have transmitted elements of their culture, how ancient people worshipped, developed astrologies, and honored seasonal cusps that, for modern civilization, have devolved into all but distractions in a whirlwind, technocentric world.

History of archaeoastronomy

A half century before archaeoastronomy had "grown up" enough to learn its modern name, Stonehenge as an Astronomical Instrument was among the first articles in Antiquity, the quarterly review of archaeology, in its premiere edition published in 1927.

Oddly enough, it was Great Britain's 19th century nationalistic debate on metrology, specifically pitting the French metric system against the British imperial system of measurements, that was the main catalyst in igniting interest in archaeoastronomy. In 1859 London literary mogul John Taylor's The Great Pyramid: Why It Was Built? and Who Built It? adopted beliefs first advanced centuries earlier by Italian mathematician Gerolamo Cardano and later Oxford Professor of astronomy John Greaves. Having surveyed Egyptian pyramids in 1638, Greaves wrote The Origine and Antiquity of Our English Weights and Measures Discover'd. Neither a scientist nor a visitor to Egypt, Taylor triumphed the British inch, virtually identical to the sacred inch of The Great Pyramid, which he contended was the bank of measurements approved by God. A convert to Taylor's ideas, Astronomer Royal of Scotland Charles Piazzi Smyth wrote Our Inheritance in the Great Pyramid in 1864, the year Taylor died, then went to Egypt to do his own survey. As a champion for a cause that also viewed the monument as symbolic of biblical prophecy, Piazzi Smyth fell out of favor with scientists, and resigned his fellowship in the Royal Society of London in 1874. Among his leading critics was James Bonwick, Fellow of the Royal Geographic Society, and author of Pyramid Facts and Fancies in 1877 and Egyptian Belief and Modern Thought in 1878. The tide was turning.

Far removed from the Anglican firestorm, Chicago M.D. Everett W. Fish wrote The Egyptian Pyramids: An Analysis of A Great Mystery, published in January 1880. Fish invoked the Baconian method of scientific inquiry in his study of astronomical features. He criticized Piazzi Smyth for over-reaching, but favored Piazzi Smyth's faith over Bonwick's agnosticism. Although clearly awed about measures of the monument analogous to the year and earth's distance from the sun, among other coincidences (divinely-inspired or not), Fish shared his scientific insights, as well (page 132):

The almost astronomically exact orientation of the Great Pyramid is indeed a remarkable feature. Without knowledge of the earth's shape, or motions, and an exact line from Alcyone to Draconis, the east-and-west, or north-and-south direction of the sides could not have been accomplished. It never did occur in other ancient buildings. Glidden remarks that this feature indicates that they were familiar with the compass, but it is known that the needle always points several degree west of the direct north pole. The sun's rising would have been of no avail, for it varied from equinox to equinox. Altogether, the placing (of) the structure east and west correctly is corroboration of the astronomical date of the Pyramid's erection.

Then, in 1883 British astronomer Richard Anthony Proctor's The Great Pyramid: Observatory, Tomb and Temple fully rejected Piazzi Smyth's mysticism and embraced pure science. On page 177 Proctor noted an ancient commentary on Plato's Timaeus:

For we learn from Proclus that the pyramids of Egypt (which, according to Diodorus, had existed 3,600 years before his history was written, about 8 B.C.) terminated above in a platform, from which priests made their celestial observations.

The first author of a genuinely scientific book, at least penned in English, about what was later to be known as archaeoastronomy, is a narrow call between either Dr. Fish or Royal Astronomical Society fellow Proctor.

British astronomer Joseph Lockyer added more to this body of literature in 1894 with The Dawn of Astronomy: A Study of Temple-Worship and Mythology of the Ancient Egyptians, followed a dozen years later with analysis of a subject closer to home, Stonehenge and Other British Stone Monuments Astronomically Considered. Contemporaneously, archaeologist Francis Penrose wrote extensively about astronomical alignments of Greek temples in the Philosophical Transactions of the Royal Society. This subject seems to have been introduced in Chapter 6 of archaeologist Heinrich Nissen's 1869 book Das Templum: Antiquarische Untersuchungen (The Temples: Antiquarian Investigations), however any credit should be shared with fellow German, Bremen University professor Dr. B. Thiel, author of an appendix including remarks, Astronomical Auxiliary Tables, page 233 via the preceding citation. This book remains untranslated into English even today. Nissen, an epigrapher as well, included many Latin and Greek citations within his book.

In the radicalized 1960s, a schism developed between two archaeoastromers performing independent research and an archaeological establishment uncomfortable with their bold implications. In quick succession these two professors from prestigious universities, one American, the other English, were theorizing megalithic stone circles, particularly the most famous, in the British Isles had been assembled with far more care and astronomical purpose than previously thought. Boston University astronomy professor Gerald Hawkins claimed, in the journal Nature in 1963, to have discovered, aided by computer analysis, 165 significant features including a dozen key solar and lunar alignments integrated into the circular Stonehenge complex. Two years later, Hawkins' findings were assembled in his book, Stonehenge Decoded; and two years after that, Oxford professor of engineering Alexander Thom came out with the first in a trilogy that deduced, from his having carefully surveyed many megalithic circles, a precise and profound ancient system that divided the year into eight, nearly equivalent intervals bracketed by solstices, equinoxes and their bisects, cross-quarter dates. Stonehenge archaeologist Richard J. C. Atkinson denounced Hawkins, while Clive Ruggles challenged whether the evidence merited Thom's conclusions. His work ultimately was vindicated by investigative digs led by archaeologist Euan MacKie, who then proceeded to author new prehistories of Britain, citing Thom's research.

Meanwhile, the Atlantic Ocean was becoming a figurative gulf for a schism threatening to cripple the toddler that was archaeoastronomy. Healing of the rift began at the first International Conference on Archaeoastronomy in Oxford, England, sponsored by the IAU. Field work in the UK, Egypt and Greece had used a purely statistical approach in collecting data for the interpretation of stone circles, pyramids and temples, while researchers in the West, analyzing petroglyphs, earthen mounds, runes, and a few megalithic sites along the northeastern US seaboard, had accessed some early colonial reports based on Amerindian ethnographies. The 1981 conference report was published in two separate volumes because of the distinctive methodologies. In subsequent Oxford conferences held every four or five years in locations around the world, compromise, the sharing of techniques, as well as new advanced technology research tools have improved methodologies for both East and West. Rather than merely establishing the existence of ancient astronomies, archaeoastronomers now seek to explain why people would have an interest in the night sky.

Controversies regarding archaeoastronomy

Archaeoastronomy is controversial in some academic circles which claim scientific methodology loses its authority in this particularly popular field of inquiry. On the other hand, some avocational practitioners enter with an idealism that must be tempered with pragmatism. Although often schooled to critically test scientific hypotheses, many are surprised that, by and large, professional preservationists have little or no desire to investigate, much less embrace, suspected archaeoastronomical discoveries.

Methodology

Early archaeoastronomy began by surveying alignments of Megalithic stones in the British Isles and sites like Auglish in County Londonderry in an attempt to find statistical patterns

Because of the wide variety of evidence, which can include artifacts as well as sites, there is no one way to practice archaeoastronomy. Despite this it is accepted that Archaeoastronomy is not a discipline that sits in isolation. Because Archaeoastronomy is an interdisciplinary field, whatever is being investigated should make sense both archaeologically and astronomically. Studies are more likely to be considered sound if they use theoretical tools found in Archaeology like analogy and homology and if they can demonstrate an understanding of accuracy and precision found in Astronomy.

Artifactual analysis

The Antikythera mechanism (main fragment)

In the case of artifacts such as the Sky Disc of Nebra, alleged to be a Bronze Age artifact depicting the cosmos, the analysis would be similar to typical post-excavation analysis as used in other sub-disciplines in archaeology. An artifact is examined and attempts are made to draw analogies with historical or ethnographical records of other peoples. The more parallels that can be found, the more likely an explanation is to be accepted by other archaeologists.

Another well-known artifact with an astronomical use is the Antikythera mechanism. In this case analysis of the artifact, and reference to the description of similar devices described by Cicero, would indicate a plausible use for the device. The argument is bolstered by the presence of symbols on the mechanism, allowing the disc to be read.

Symbolic analysis

Diagram showing the location of the sun daggers on the Fajada Butte petroglyph on various days

In some cases the use of an artefact may be known, but its meaning may not be fully understood. In such cases an examination of the symbolism on the artefact may be necessary.

A mundane example is the presence of astrological symbols found on some shoes and sandals from the Roman Empire. The use of shoes and sandals is well known, but Carol van Driel-Murray has proposed that astrological symbols etched onto sandals gave the footwear spiritual or medicinal meanings. This is supported through citation of other known uses of astrological symbols and their connection to medical practice and with the historical records of the time.

More problematic are some petroglyphs. Symbols on rock are one such class of symbol which are occasionally argued to posses astronomical meanings. An example is the Sun Dagger of Fajada Butte which is a glint of sunlight passing over a spiral petroglyph. The location of the dagger on the petroglyph varies throughout the year. At the solstices a dagger can be seen either through the heart of the spiral or to either side of it. It is proposed that this petroglyph was created to mark these events. If no ethnographic nor historical data are found which can support this assertion then acceptance of the idea relies upon the reader’s own belief as to whether or not there are enough petroglyph sites in North America that such a correlation could occur by chance. It is helpful when petroglyphs are associated with existing peoples. This allows ethnoastronomers to question informants as to the meaning of such symbols.

Alignment analysis

The Sun rising behind the Heel Stone at Stonehenge

One aspect of archaeoastronomy is alignment analysis, the study of the orientation of constructs and structures and calculation of the relation of the direction in which they faced with astronomical events. Stonehenge's Avenue is hypothesized to have an orientation to the summer solstice sunrise. In pyramids of Egypt are oriented in the cardinal directions.

Alignment analysis may vary depending upon the researcher. As a coarse stereotype archaeoastronomers from an historical background tend to have an idea which is then tested by examining structures for alignments. Astronomically-minded archaeoastronomers may analyze large numbers of sites and attempt to find statistical patterns. This approach was employed in papers by pioneers in the field. Alexander Thom conducted extensive survey work of megalithic stone circles and concluded many sites were situated to observe the moon. In this instance the aim was to prove that there is an astronomical problem which requires an historical explanation. This latter approach continues to an extent in some modern research but it has comparatively little direct impact on mainstream archaeology.

One reason the statistically-led approach has proven unpopular with archaeologists and anthropologists was stated by the anthropologist Keith Kintigh:

In light of the fact that archaeoastronomers bring considerable energy and expertise to their efforts, what accounts for archaeologists’ indifference?

I think the principal reason is that archaeologists see archaeoastronomers as answering questions that, from a social scientific standpoint, no one is asking. To put it bluntly, in many cases it doesn’t matter much to the progress of anthropology whether a particular archaeoastronomical claim is right or wrong because the information doesn’t inform the current interpretive questions.

Recent statistically led research has tended to be more discriminating, choosing archaeologically associated sites and where possible referring back to historical or ethnographic records to place the findings in a social context.

An alignment is calculated by measuring the azimuth, the angle from north, of the structure and the altitude of the horizon it faces. The azimuth is usually measured using a theodolite or a compass. A compass is easier to use, though the deviation of the Earth’s magnetic field from true north, known as its magnetic declination must be taken into account. Compasses are also unreliable in areas prone to magnetic interference, such as sites being supported by scaffolding. Additionally a compass can only measure the azimuth to a precision of a half a degree.

A theodolite can be considerably more accurate if used correctly, but it is also considerably more difficult to use correctly. There is no inherent way to align a theodolite with North and so the scale has to be calibrated using astronomical observation, usually the position of the Sun. Because the position of celestial bodies changes with the time of day due to the Earth’s rotation, the time of these calibration observations must be accurately known, or else there will be a systematic error in the measurements. Horizon altitudes can be measured with a theodolite or a clinometer.

Recreating the ancient sky

Once the researcher has data to test, it is often necessary to attempt to recreate ancient sky conditions to place the data in its historical environment.

Declination

Main article: Declination

A time lapse photo showing the stars rotating around the celestial pole.

To calculate what astronomical features a structure faced a coordinate system is needed. The stars provide such a system. If you were to go outside on a clear night you would observe the stars spinning around the celestial pole. This point is +90° if you are watching the North Celestial Pole or −90° if you are observing the Southern Celestial Pole. The concentric circles the stars trace out are lines of celestial latitude, known as declination. The arc connecting the points on the horizon due East and due West (if the horizon is flat) and all points midway between the Celestial Poles is the Celestial Equator which has a declination of 0°. The visible declinations vary depending where you are on the globe. Only an observer on the North Pole of Earth would be unable to see any stars from the Southern Celestial Hemisphere at night (see diagram below). Once a declination has been found for the point on the horizon that a building faces it is then possible to say if a specific body can be seen in that direction.

Diagram of the visible portions of sky at varying latitudes.

Solar positioning

While the stars are fixed to their declinations the Sun is not. The rising point of the Sun varies throughout the year. It swings between two limits marked by the solstices a bit like a pendulum, slowing as it reaches the extremes, but passing rapidly through the mid-point. If an archaeoastronomer can calculate from the azimuth and horizon height that a site was built to view a declination of +23.5° then he need not wait until June 21 to confirm the site does indeed face the summer solstice. For more information see History of solar observation.

Lunar positioning

The Moon’s appearance is considerably more complex. Its motion, like the Sun, is between two limits — known as lunastices rather than solstices. However, its travel between lunastices is considerably faster. It takes a sidereal month to complete its cycle rather than the year long trek of the Sun. This is further complicated as the lunastices marking the limits of the Moon’s movement move on an 18.6 year cycle. For slightly over nine years the extreme limits of the moon are outside the range of sunrise. For the remaining half of the cycle the Moon never exceeds the limits of the range of sunrise. However, much lunar observation was concerned with the phase of the Moon. The cycle from one New Moon to the next runs on an entirely different cycle, the Synodic month. Thus when examining sites for lunar significance the data can appear sparse due the extremely variable nature of the moon. See Moon for more details.

Stellar positioning

Main article: Precession of the equinoxes

Precessional movement.

Finally there is often a need to correct for the apparent movement of the stars. On the timescale of human civilisation the stars have maintained the same position relative to each other. Each night they appear to rotate around the celestial poles due to the Earth’s rotation about its axis. However, the Earth spins rather like a spinning top. Not only does the Earth rotate, it wobbles. The Earth’s axis takes around 25700 years to complete one full wobble. The effect to the archaeoastronomer is that stars did not rise over the horizon in the past in the same places as they do today. Nor did the stars rotate around Polaris as they do now. In the case of the Egyptian pyramids, it has been shown they were aligned towards Thuban, a faint star in the constellation of Draco. The effect can be substanstial over relatively short lengths of time, historically speaking. For instance a person born on December 25 in Roman times would have been born under the astrological sign of Capricorn. In the modern period a person born on the same date is now a Sagittarian due to the precession of the equinoxes.

Transient phenomena

Halley’s Comet depicted on the Bayeux tapestry

Additionally there are often transient phenomena, events which do not happen on an annual cycle. Most predictable are events like eclipses. In the case of solar eclipses these can be used to date events in the past. A solar eclipse mentioned by Herodotus enables us to date a battle between the Medes and the Lydians, which following the eclipse failed to happen, to May 28, 585 BC. Other easily calculated events are supernovae whose remains are visible to astronomers and therefore their positions and magnitude can be accurately calculated.

Some comets are predictable, most famously Halley’s Comet. Yet as a class of object they remain unpredictable and can appear at any time. Some have extremely lengthy orbital periods which means their past appearances and returns cannot be predicted. Others may have only ever passed through the solar system once and so are inherently unpredictable.

Meteor showers should be predictable, but the meteors are cometary debris and so require calculations of orbits which are currently impossible to complete. Other events noted by ancients include aurorae, sun dogs and rainbows all of which are as impossible to predict as the ancient weather, but nevertheless may have been considered important phenomena.

Meteorite impacts and bolide explosions are also significant and do not occur at predictable times. On occasion, these impacts occur during meteor showers, while larger, more isolated cases occur and a relatively frequent basis. One such example is the alleged Umm al Binni impact crater in Iraq, which may help explain the fall of Mesopotamian civilization as well as the 2200 BCE anomaly. Passages in the Epic of Gilgamesh as well as Biblical Revelations seem to describe meteorite impacts.

Major topics of archaeoastronomical research

The use of calendars

Aztec Stone of the Sun replica in El Paso, Texas, cast from the original to be found in Mexico's National Museum of Anthropology. A religious artefact showing how the Mexica people thought about time.

A common justification for the need for astronomy is the need to develop an accurate calendar for agricultural reasons. Ancient texts like Hesiod’s Works and Days, an ancient farming manual, would appear to contradict this. Instead astronomical observations are used in combination with ecological signs, such as bird migrations to determine the seasons. Ethnoastronomical work with the Mursi of Ethiopia shows that haphazard astronomy continued until recent times in some parts of the world. All the same, calendars appear to be an almost universal phenomenon in societies as they provide tools for the regulation of communal activities.

An example of a non-agricultural calendar is the Tzolk'in calendar of the Maya civilization of pre-Columbian Mesoamerica, which is a cycle of 260 days. This count is based on an earlier calendar and is found throughout Mesoamerica. This formed part of a more comprehensive system of Maya calendars which combined a series of astronomical observations and ritual cycles.

Other peculiar calendars include ancient Greek calendars. These were nominally lunar, starting with the New Moon. In reality the calendar could pause or skip days with confused citizens inscribing dates by both the civic calendar and ton theoi, by the moon. The lack of any universal calendar for ancient Greece suggests that coordination of panhellenic events such as games or rituals could be difficult and that astronomical symbolism may have been used as a politically neutral form of timekeeping.

Myth and cosmology

The constellation Argo Navis drawn by Johannes Hevelius in 1690.

Another motive for studying the sky is to understand and explain the universe. In pre-scientific times myth was a tool for achieving this and the explanations, while not scientific, are cosmologies.

The Incas arranged their empire to demonstrate their cosmology. The capital, Cusco, was at the centre of the empire and connected to it by means of ceques, conceptually straight lines radiating out from the centre. These ceques connected the centre of the empire to the four suyus, which were regions defined by their direction from Cusco. The notion of a quartered cosmos is common across the Andes. Gary Urton, who has conducted fieldwork in the Andean villagers of Misminay, has connected this quartering with the appearance of the Milky Way in the night sky. In one season it will bisect the sky and in another bisect it in a perpendicular fashion.

The importance of observing cosmological factors is also seen on the other side of the world. The Forbidden City in Beijing is laid out to follow cosmic order though rather than observing four directions the Chinese saw five, North, South, East, West and Centre. The Forbidden City occupied the centre of ancient Beijing. One approaches the Emperor from the south, thus placing him in front of the circumpolar stars. This creates the situation of the heavens revolving around the person of the Emperor. The Chinese cosmology is now better known through its export as Feng Shui.

There is also much information about how the universe was thought to work stored in the mythology of the constellations. The Barasana of the Amazon plan part of their annual cycle based on observation of the stars. When their constellation of the Caterpillar-Jaguar falls they prepare to catch the pupating caterpillars of the forest as they fall from the trees. This provides planning for food procurement at a time when hunger could otherwise be a problem.

A more well-known source of constellation myth are the texts of the Greeks and Romans. The origin of their constellations remains a matter of continuing and occasionally fractious debate.

Displays of power

The Intihuatana (“tie the sun”) at Machu Picchu is believed to have been designed as an astronomic clock by the Incas, while some have speculated about the site’s possible astrological role

The most common popular image of archaeoastronomy is the expression of hidden knowledge and power. By using stellar symbolism one can make claims of heavenly power.

By including celestial motifs in clothing it becomes possible for the wearer to make claims the power on Earth is drawn from above. It has been said that the Shield of Achilles described by Homer is also a catalogue of constellations. In North America shields depicted in Comanche petroglyphs appear to include Venus symbolism.

Solsticial alignments also can be seen as displays of power. In Egypt the temple of Amun-Re at Karnak has been the subject of much study. Evaluation of the site, taking into account the change over time of the obliquity of the ecliptic show that the Great Temple was aligned on the rising of the midwinter sun. The length of the corridor down which sunlight would travel would have limited illumination at other times of the year.

In a later period the Serapeum in Alexandria was also said to have contained a solar alignment so that, on a specific sunrise, a shaft of light would pass across the lips of the statue of Serapis thus symbolising the Sun saluting the god.

The use of astronomy at Stonehenge continues to be a matter of vigorous discussion.

Archaeoastronomical organisations and publications

There are currently two academic organisations for scholars of archaeoastronomy. ISAAC—the International Society for Archaeoastronomy and Astronomy in Culture—was founded in 1995 and now sponsors the Oxford conferences and Archaeoastronomy — the Journal of Astronomy in Culture. SEAC—the Société Européenne pour l’Astronomie dans la Culture—is slightly older; it was created in 1992. SEAC holds annual conferences in Europe and publishes refereed conference proceedings on an annual basis.

Additionally the Journal for the History of Astronomy publishes many archaeoastronomical papers. For twenty-seven volumes it also published an annual supplement Archaeoastronomy.

See also

• Cultural astronomy
• List of archaeoastronomical sites sorted by country Sites where claims for the use of astronomy have been made.
• List of artefacts of archaeoastronomical significance Artefacts which have been interpreted as being used for some astronomical purpose.
• European Megalithic Culture
• Australian Aboriginal Astronomy
  • Aboriginal stone arrangements
• Lunar standstill
• Medicine wheels
• Mound builders
• Petroforms
• Megalithic geometry

External links

• Archaeoastronomy A Thinkquest website surveying archaeoastronomical sites across the world.
• Clive Ruggles' webpages: images, bibliography, software, and materials from his course at the University of Leicester
• ISAAC, The International Society for Archaeoastronomy and Astronomy in Culture.
• SEAC La Société Européenne pour l’Astronomie dans la Culture. Site in English.
• SIAC La Sociedad Interamericana de Astronomía en la Cultura.
• Space Imaging’s Ancient Observatories gallery — Satellite pictures of ancient observatories.
• Traditions of the Sun — NASA and others exploring the world’s ancient observatories.
• Tulum — Mayan Mystery — Amateur archaeoastronomy from the archaeological site at Tulum.
• Australian Aboriginal Astronomy
• Stonehenge and Other British Stone Monuments Astronomically Considered - etext at sacred-texts.com
• Amateur Archeoastronomy of Mayan Copan Ruinas
• Society for the History of Astronomy
• High Precision Archaeoastronomy Eclipse Detector
• siloam.net - overview of celestial metaphors
• Persian Archaeoastronomy

Journals

• Archaeoastronomy and Ethnoastronomy News
• Archaeoastronomy: Supplement to the Journal for the History of Astronomy
• Archaeoastronomy: The Journal of Astronomy in Culture
• Culture and Cosmos
• Journal for the History of Astronomy