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==History of archaeoastronomy== | ==History of archaeoastronomy== | ||
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Archaeoastronomy is almost as old as archaeology itself. Heinrich Nissen was arguably the first archaeoastronomer, publishing a systematic survey of the orientations of Greek Temples in ''Das Templum: Antiquarische Untersuchungen'' in 1869.<ref>C.L.N. Ruggles, ''Ancient Astronomy'', ABC-Clio, 2005, 419,471, ISBN 1851094776</ref> Other researchers followed. The astronomer ] was active at the end of the nineteenth century and the start of the ]. His studies included an examinations of Egyptian temples in ''The Dawn of Astronomy'' in 1894 and of Stonehenge published as ''Stonehenge and Other British Stone Monuments Astronomically Considered'' in 1906. The archaeologist ] published extensively in the '']'' on the astronomical alignment of ]s in the ] in the same period. Archaeoastronomy was, for a while, a respectable subject. The first issue of the archaeological journal ], published in 1927, includes an article on archaeoastronomical research.<ref>A.P. Trotter, , '']'' Vol 1:1, 1927, 42–53</ref> | |||
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] of Giza (a.k.a. Kheops or Khufu) near Cairo, Egypt, constructed ~2570 BCE, world's tallest building until 1300 CE]] | |||
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]</center><center>(1501-1576)</center>Italian mathematician and inventor, friend of ]]] | |||
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]</center><center>(1819-1900)</center>professor of astronomy, University of Edinburgh and Astronomer Royal of Scotland from 1845 to 1888]] | |||
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]</center><center>(1837-1888)</center>British astronomer, prolific author, international lecturer]] | |||
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]</center><center>(1836-1920)</center>British astronomer esp. solar, founded science journal ] in 1869]] | |||
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] in an attempt to find statistical patterns]] | |||
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] sites such as ] were built in accordance with astronomical alignments]] | |||
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In 1927, decades before archaeoastronomy had grown up enough to even find its name, "Stonehenge as an Astronomical Instrument" led off among the articles in the premiere edition of the quarterly review of archaeology, "Antiquity".<ref>A.P. Trotter, , '']'' Vol 1:1, 1927, 42–53</ref> | |||
] in ] in an attempt to find statistical patterns]]In the ] interest in archaeoastronomy waned until the 1960s when the astronomer ] proposed that ] was a ] computer. Around the same time the engineer ] published his survey results of ]ic sites also proposed widespread practice of accurate astronomy in the British Isles. The claims of Hawkins were largely dismissed.<ref>], , '']'' Vol 49:159, 1966, 212–6</ref> However, Thom’s analysis continued to pose a problem. A re-evaluation of Thom’s fieldwork by Clive Ruggles attempted to show that his claims of high accuracy astronomy were not fully supported by the evidence. Nevertheless there was evidence of widespread interest in astronomy associated with megalithic sites. The response from most archaeologists was tepid. Only one, Euan MacKie, recognised that Thom’s theories needed to be tested and he excavated at the Kintraw standing stone site in Argyllshire in 1970 and 1971 to check whether the latter’s prediction of an observation platform on the hill slope above the stone was correct. There was an artificial platform there and this apparent verification of Thom’s long alignment hypothesis (Kintraw was diagnosed as an accurate winter solstice site) led him to check Thom’s geometrical theories at the Cultoon stone circle in Islay, also with a positive result. MacKie therefore broadly accepted Thom’s conclusions and published new prehistories of Britain.<ref>E. MacKie, ''Science and Society in Prehistoric Britain'', Paul Elek, 1977, ISBN 0-236-40041-X</ref> Until the early 1980s — with the exception just mentioned — most archaeoastronomical research in the United Kingdom was concerned with establishing the existence of astronomical alignments in prehistoric sites by ] means rather than the social practice of astronomy in ancient times. | |||
Oddly enough, a 19th century nationalistic debate on ], specifically pitting the French metric system against the British imperial system of measurements,<ref>Eric Michael Reisenauer, "The battle of the standards: great pyramid metrology and British identity, 1859-1890", The Historian, 2003, </ref> proved to be a catalyst in igniting interest in archaeoastronomy. In 1859 London literary mogul ]'s "The Great Pyramid: Why It Was Built? and Who Built It?" adopted beliefs first advanced centuries earlier by Italian mathematician ] and later Oxford Professor of astronomy ]. 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 ] 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 fell out of favor with scientists, and resigned his fellowship in the ] in 1874. Among his leading critics was James Bonwick, Fellow of the ], and author of "Pyramid Facts and Fancies" in 1877 and "Egyptian Belief and Modern Thought" in 1878. The tide was turning. | |||
] sites such as ] were built in accordance with astronomical alignments]]In the ], anthropologists began to more fully consider the role of astronomy in ] societies. This approach had access to sources that the ] of Europe lacks such as ]<ref>M. Zeilik, The Ethnoastronomy of the Historic Pueblos, I: Calendrical Sun Watching, ''Archaeoastronomy'' No. 8 (Supplement to the ''Journal for the History of Astronomy''), 1985, pp. S1–S24; The Ethnoastronomy of the Historic Pueblos, II: Moon Watching, ''Archaeoastronomy'' No. 10 (Supplement to the ''Journal for the History of Astronomy''), 1986, pp. S1–S22.</ref> and the ] records of the early ]. This allowed New World archaeoastronomers to make claims for motives which in the Old World would have been mere speculation. The concentration on historical data led to some claims of high accuracy that were comparatively weak when compared to the statistically led investigations in Europe. | |||
Far removed from the Anglican firestorm, Chicago M.D. Everett W. Fish wrote "The Egyptian Pyramids: An Analysis of A Great Mystery",<ref>Everett W. Fish, M.D., "The Egyptian Pyramids: An Analysis of A Great Mystery", C.H. Jones & Company, 1880, (not copyrighted), digitized selected pages 112-146</ref> published in January 1880. Fish invoked the ] of scientific inquiry in his study of astronomical features. He criticized Piazzi for over-reaching, but favored Piazzi's faith over Bonwick's agnosticism. Then, in 1883 British astronomer ]'s "The Great Pyramid: Observatory, Tomb and Temple"<ref>Richard Anthony Prior, "The Great Pyramid: Observatory, Tomb and Temple", Chatto & Windus, 1883, digitized book</ref> fully rejected Piazzi's spin and embraced pure science. On page 177 Proctor noted an ancient commentary on Plato's "Timaeus": | |||
This came to a head at a meeting sponsored by the ] in ] in 1981.<ref>C.L.N. Ruggles, ''Archaeoastronomy in the 1990s'', Group D Publications. 1993, ix, ISBN 1-874152-01-2</ref> The ] and research questions of the participants were considered so different that the conference proceedings were published as two volumes.<ref>A. F. Aveni (ed.), ''Archaeoastronomy in the New World: American Primitive Astronomy'', ], 1982, ISBN 0-521-24731-4; D. C. Heggie (ed.), ''Archaeoastronomy in the Old World'', ], 1982, ISBN 0-521-24734-9 </ref> Nevertheless the conference was considered a success in bringing researchers together and Oxford conferences have continued every four or five years at locations around the world. The subsequent conferences have resulted in a move to more interdisciplinary approaches with researchers aiming to combine the contextuality of archaeological research,<ref>A.F. Aveni, ''World Archaeoastronomy'', ], 1989, xi–xiii, ISBN 0-521-34180-9</ref> which broadly describes the state of archaeoastronomy today. Rather than merely establishing the existence of ancient astronomies archaeoastronomers seek to explain why people would have an interest in the night sky. | |||
<blockquote>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.</blockquote> | |||
The first scientific author of a published book, at least in English, about what was later to be known as archaeoastronomy, can arguably be narrowed to a choice between Dr. Fish and ] fellow Proctor. | |||
British astronomer ] 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 ] wrote extensively about astronomical alignments of s in the . This particular topic seems to have been first introduced in Chapter 6 of archaeologist Heinrich Nissen's 1869 book "Das Templum: Antiquarische Untersuchungen (The Temples: Antiquarian Investigations)",<ref>Heinrich Nissen, "Das Templum: Antiquarische Untersuchungen", Weidmannsche Buchhandslung, 1869, digitized book, tabbed to Chapter 6, "Die Orientirung des Templum (The Orientation of the Temples)"</ref> 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 ] 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 ] 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, ] dates. Stonehenge archaeologist ] denounced Hawkins,<ref>], , '']'' Vol 49:159, 1966, 212–6</ref> 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,<ref>E. MacKie, ''Science and Society in Prehistoric Britain'', Paul Elek, 1977, ISBN 0-236-40041-X</ref> 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<ref>C.L.N. Ruggles, ''Archaeoastronomy in the 1990s'', Group D Publications. 1993, ix, ISBN 1-874152-01-2</ref> in Oxford, England, sponsored by the ]. 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 ].<ref>M. Zeilik, The Ethnoastronomy of the Historic Pueblos, I: Calendrical Sun Watching, ''Archaeoastronomy'' No. 8 (Supplement to the ''Journal for the History of Astronomy''), 1985, pp. S1–S24; The Ethnoastronomy of the Historic Pueblos, II: Moon Watching, ''Archaeoastronomy'' No. 10 (Supplement to the ''Journal for the History of Astronomy''), 1986, pp. S1–S22.</ref> The 1981 conference report was published in two separate volumes because of the distinctive methodologies.<ref>A. F. Aveni (ed.), ''Archaeoastronomy in the New World: American Primitive Astronomy'', ], 1982, ISBN 0-521-24731-4; D. C. Heggie (ed.), ''Archaeoastronomy in the Old World'', ], 1982, ISBN 0-521-24734-9 </ref> 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 ] for both East and West.<ref>A.F. Aveni, ''World Archaeoastronomy'', ], 1989, xi–xiii, ISBN 0-521-34180-9</ref> Rather than merely establishing the existence of ancient astronomies, archaeoastronomers now seek to explain why people would have an interest in the night sky. | |||
==Methodology== | ==Methodology== |
Revision as of 08:00, 5 January 2008
Archaeoastronomy (also spelled archeoastronomy) is the study of ancient or traditional astronomies in their cultural context, utilising archaeological and anthropological evidence. The anthropological study of astronomical practices in contemporary societies is often called ethnoastronomy, although there is no consensus as to whether ethnoastronomy is a separate discipline or is a part of archaeoastronomy. Archaeoastronomy is also closely associated with historical astronomy, the use of historical records of heavenly events to answer astronomical problems and the history of astronomy, which uses written records to evaluate past astronomical traditions.
History of archaeoastronomy
In 1927, decades before archaeoastronomy had grown up enough to even find its name, "Stonehenge as an Astronomical Instrument" led off among the articles in the premiere edition of the quarterly review of archaeology, "Antiquity".
Oddly enough, a 19th century nationalistic debate on metrology, specifically pitting the French metric system against the British imperial system of measurements, proved to be a 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 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 for over-reaching, but favored Piazzi's faith over Bonwick's agnosticism. Then, in 1883 British astronomer Richard Anthony Proctor's "The Great Pyramid: Observatory, Tomb and Temple" fully rejected Piazzi's spin 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 scientific author of a published book, at least in English, about what was later to be known as archaeoastronomy, can arguably be narrowed to a choice between Dr. Fish and 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 s in the . This particular topic seems to have been first 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.
Methodology
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
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
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
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: DeclinationTo 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.
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 equinoxesFinally 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
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
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
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 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.
References
- A.P. Trotter, Stonehenge as an Astronomical Instrument, Antiquity Vol 1:1, 1927, 42–53
- Eric Michael Reisenauer, "The battle of the standards: great pyramid metrology and British identity, 1859-1890", The Historian, 2003, HighBeam Encyclopedia
- Everett W. Fish, M.D., "The Egyptian Pyramids: An Analysis of A Great Mystery", C.H. Jones & Company, 1880, (not copyrighted), archaeoastronomy.com digitized selected pages 112-146
- Richard Anthony Prior, "The Great Pyramid: Observatory, Tomb and Temple", Chatto & Windus, 1883, Google digitized book
- Heinrich Nissen, "Das Templum: Antiquarische Untersuchungen", Weidmannsche Buchhandslung, 1869, Google digitized book, tabbed to Chapter 6, "Die Orientirung des Templum (The Orientation of the Temples)"
- Richard J. C. Atkinson, Moonshine on Stonehenge, Antiquity Vol 49:159, 1966, 212–6
- E. MacKie, Science and Society in Prehistoric Britain, Paul Elek, 1977, ISBN 0-236-40041-X
- C.L.N. Ruggles, Archaeoastronomy in the 1990s, Group D Publications. 1993, ix, ISBN 1-874152-01-2
- M. Zeilik, The Ethnoastronomy of the Historic Pueblos, I: Calendrical Sun Watching, Archaeoastronomy No. 8 (Supplement to the Journal for the History of Astronomy), 1985, pp. S1–S24; The Ethnoastronomy of the Historic Pueblos, II: Moon Watching, Archaeoastronomy No. 10 (Supplement to the Journal for the History of Astronomy), 1986, pp. S1–S22.
- A. F. Aveni (ed.), Archaeoastronomy in the New World: American Primitive Astronomy, CUP, 1982, ISBN 0-521-24731-4; D. C. Heggie (ed.), Archaeoastronomy in the Old World, CUP, 1982, ISBN 0-521-24734-9
- A.F. Aveni, World Archaeoastronomy, CUP, 1989, xi–xiii, ISBN 0-521-34180-9
- C. van Driel-Murray, Regarding the Stars, TRAC 2001: Proceedings of the Eleventh Annual Theoretical Roman Archaeology Conference Glasgow 2001. eds. M Carruthers, C. van Driel-Murray, A. Gardner, J. Lucas, L. Revell and E. Swift. Oxbow Books. 2002, 96–103, ISBN 1-84217-075-9
- K. Spence, Ancient Egyptian Chronoology and the astronomical orientation of the pyramids, Nature, Vol 406, 16 November 2000, 320–324.
- K. Kintigh, I wasn’t going to say anything, but since you asked: Archaeoastronomy and Archaeology, Archaeoastronomy & Ethnoastronomy News 5, 1992
- Brunton Pocket Transit Instruction Manual, p. 22
- Astrological Things What is Your Sign, Really ?
- Herodotus, The Histories, I.74
- D. Turton and C.L.N. Ruggles, Agreeing to Disagree: The Measurement of Duration in a Southwestern Ethiopian Community, Current Anthropology Vol. 19.3, 1978, 585–600
- A.F. Aveni, Empires of Time, Basic Books, 1989, ISBN 0-465-01950-1
- S. McCluskey, The Inconstant Moon: Lunar Astronomies in Different Cultures, Archaeoastronomy: The Journal of Astronomy in Culture Vol 15. 2000, 14–31
- A. Salt and E. Boutsikas, Knowing when to consult the oracle at Delphi. Antiquity Vol 79:305, 2005, 562–72
- B. Bauer and D. Dearborn, Astronomy and empire in the ancient Andes: the cultural origins of Inca sky watching, University of Texas, 1995, ISBN 0-292-70837-8
- G. Urton, At the crossroads of the earth and the sky: an Andean cosmology, University of Texas. 1981, ISBN 0-292-70349-X
- E.C. Krupp, Skywatchers, Shamans and Kings, John Wiley and Sons, 1997, 196–9, ISBN 0-471-32975-4
- M. Hoskin, The Cambridge Concise History of Astronomy, CUP, 1999, 15–6, ISBN 0-521-57600-8
- R. Hannah, The Constellations on Achilles’ Shield (Iliad 18. 485–489). Electronic Antiquity II.4, 1994, 15–6
- E.C. Krupp, Skywatchers, Shamans and Kings, John Wiley and Sons, 1997, 252–3, ISBN 0-471-32975-4
- E.C. Krupp, Light in the Temples, Records in Stone: Papers in Memory of Alexander Thom, ed. C.L.N. Ruggles, 1988, 473–499, ISBN 0-521-33381-4
- Rufinus, The destruction of the Serapeum
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
- 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
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