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PostPosted: Sat Oct 27, 2012 5:43 am 
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William M. O'Neil, (1912-91), Professor of Psychology at the University of Sydney, and highly regarded as one of Australia's most influential psychologists, also had a private interest in ancient astronomy.

I recently found and read his 1986 book Early Astronomy from Babylonia to Copernicus. This is a superb general introduction to early astronomy, from a highly informed amateur, full of facts, excellent in method and style, very illuminating about the core knowledge.

The chapters are
-- Introduction
-- Early Babylonian astronomy
-- Late Babylonian astronomy
-- Early Greek astronomy
-- Hipparchos
-- Ptolemy
-- The aftermath of Hellenistic astronomy
-- Astronomy and astrology
-- Arabian astronomy and its importance for the revival in the West
-- Early astronomical instruments
-- The reawakening of the West
-- Constellation and star names from ancient to modern times
-- Copernicus
-- Chinese astronomy.
-- Possible Megalithic Observatories

Publisher's Summary: Aimed specifically at amateur astronomers, this volume charts the early history and development of astronomy, from the Babylonian, Greek and Middle Eastern civilizations to the awakening of interest in the West.

I will use this thread to go through this book chapter by chapter, highlighting information that is of interest from an astrotheological perspective.


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PostPosted: Sat Oct 27, 2012 12:15 pm 
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Ahh, good find! Thanks for posting about this book as it sounds interesting so, I'll certainly be reading your posts here as well.

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PostPosted: Sun Oct 28, 2012 1:30 am 
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Early Astronomy - Introduction

The Introduction to WM O’Neil’s Early Astronomy from Babylonia to Copernicus provides an overview and orientation to the historical story of the development of precise observation of the sky. Professor O’Neil gives particular emphasis to Babylonia or Mesopotamia, the land between the two rivers of the Tigris and Euphrates in modern-day Iraq, where he says western astronomy began nearly two thousand years before Christ. This recognition of the role of Babylonia is important in view of modern prejudice that often regards Greece as the cradle of civilization and fails to give due credit to earlier science.

O’Neil notes that the Greeks claimed to have obtained much of their star lore from Egypt, but otherwise does not discuss the land of the pyramids, perhaps since sources on their scientific knowledge have not survived.

Some points of interest raised in this chapter.
- The ecliptic, the name of the path of the sun, derived from the fact that eclipses can only occur when the moon crosses this solar circle.
- Orientation means the daily recognition of the position of the sun at dawn in the east or orient. As the ancients oriented themselves to the sky, they observed that the positions of the sun and moon and planets made orderly clockwork patterns around the ecliptic.
- The outer planets, Mars, Jupiter and Saturn, perform an annual dance, appearing to move backwards along the ecliptic with the central point of their retrograde motion marked by the date when they rise in the east at dusk. We now know this is due to the earth speeding between these planets and the sun, but the ancients lacked the information to model such motion precisely.

Yet there was steady advance in ancient knowledge, followed by the crash of Christianity, and Early Astronomy provides an accessible and clear explanation of this growth, decline and subsequent rediscovery of astronomical knowledge.

O’Neil explains that the twelve constellations of the zodiac were named in Sumeria well before the common era, and these names showed what he calls 'marked continuity' through to later times. This is of some importance given that erroneous information about late development of the zodiac division is sometimes asserted. He suggests there is evidence as early as the fourth millennium before Christ of Sumerian documentation of the four seasons of the year, and also very early knowledge of the annual movement of the stars, including the circumpolar stars that never set and the equatorial stars which disappear for months each year.

By the second millennium BC, the Babylonians used the first pre-dawn appearance each year of the stars Aldebaran (eye of the bull Taurus) and Regulus (heart of the lion Leo) to mark spring and summer respectively, and named them for these animals. At this time the Babylonians also knew the other seasons were marked by the first appearance of main stars – Antares in Scorpio for autumn and Fomalhaut near Aquarius for winter.

This observation raises one of the great ongoing controversies of early astronomy studies, whether the Babylonians knew of the precession of the equinox, a topic I will return to in discussing the chapters on Babylon and Greece. It seems intuitive that with their very accurate star records over centuries, the earliest astronomers must have noticed that Aldebaran and the others no longer provided seasonal heliacal markers. One of the most renowned modern scholars of Babylonian astronomy, Otto Neugebauer, argues the Babylonians were unaware of precession (an argument disputed by other scholars such as Schnabel and more recently Ulansey).

O’Neil provides convenient explanations of simple astronomical terms, such as declination (distance from the equator), obliquity (angle of tilt of the earth), the origin of the week in the four phases of the moon, the origin of the names of the days in the sun, moon and five visible planets, the solstices, as the points where the sun is furthest from the equator, and the equinoxes, when the sun traces the equator across the sky.

The three observed monthly cycles of the moon are of particular interest. The synodic month is named for the synod or meeting of the moon and the sun, the draconic month is named for the moon’s passage across the ecliptic at the dragon points or nodes, and the anomalistic month is named for the anomaly of the apparent speed of the moon’s motion due to its distance from the earth. The synodic month is obvious, but the precise knowledge of the draconic and anomalistic months of the moon shows the ancients were far more advanced in precise observation of the sky than is sometimes imagined.

Other topics mentioned in this introduction include the Egyptian use of heliacal rising of Sirius to mark the year, calculation of longitude at sea by knowledge of decans, and the early Greek calculation of the differing length of the seasons.


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PostPosted: Mon Oct 29, 2012 6:30 am 
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Professor O'Neil's ten page introduction to Babylonian Astronomy is at http://ojs-prod.library.usyd.edu.au/ind ... /5495/6166

For an overview of the precession debate regarding Babylon by Gary Thompson, from a scholarly sceptical perspective, see http://members.westnet.com.au/gary-davi ... page9.html

Essay Nine (9): The Myth of Babylonian Knowledge of Precession outlines the argument against early knowledge of precession. I consider this argument weak, and will return to explain why in a later post.

The essays on Thompson's page (which I have not read except #9) are quite voluminous, and well worth a look if you are interested in early astronomy.

Part 1: Investigating the Origin of the Constellations
Essay One (1): Methodologies for Investigating Constellation Origins.
Essay Two (2): Biographies of Modern Historians of Ancient Occidental Astral Sciences.

Part 2: General History of the Constellations
Essay Three (3): An Outline Sketch of the Origin and History of Constellations and Star-Names.
Essay Four (4): Chronological Development of Mesopotamian Star-Lists in the Second Millennium BCE.
Essay Five (5): The Entry of Arabic Star Names into Europe.

Part 3: Babylonian Astronomy
Essay Six (6): A Chronological History of Babylonian Astronomy.
Essay Seven (7): The Influence of Religion and Astronomy on the Development of Astrology.
Essay Eight (8): The Origin of the Zodiac.
Essay Nine (9): The Myth of Babylonian Knowledge of Precession.

Part 4: The Panbabylonism Fantasy
Essay Ten (10): The Development, Heyday, and Demise of Panbabylonism.
Essay Eleven (11): Critics and Criticisms of Hamlet's Mill

Part 5: Critiques of Popular Theories
Essay Twelve (12): Critique of Willy Hartner's Astronomical Interpretation of Lion-Bull Combat Iconography.
Essay Thirteen (13): Critique of Alexander Gurshtein's Theory of Constellation Development.
Essay Fourteen (14): Critique of John McHugh's Astronomical Interpretation of Noah's Flood.
Essay Fifteen (15): Matthew's Star an Historical Fiction.
Essay Sixteen (16): Critique of Clyde Hostetter's Ideas on Mesopotamian Bronze Age Astronomy.
Essay Seventeen (17): Some Critical Comments on "Origins of the Ancient Constellations" by John Rogers.

Part 6: Star Names and Constellations in the First Millennium BCE
Essay Eighteen (18): Mesopotamian Star Lists and Star Names in the First Millennium BCE.
Essay Nineteen (19): Greek Constellations and Constellation Myths in the First Millennium BCE.
Essay Twenty (20): The Influence of Babylonian Uranography on the Origin of the Greek constellations.

Part 7: Book Reviews
Essay Twenty-One (21): Mesopotamian Astrology: The Mother of Modern Astronomy by Swapan Kumar Adhikari (2009).


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PostPosted: Mon Oct 29, 2012 2:53 pm 
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Excellent. Thank you for taking the time to post all that.

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PostPosted: Wed Oct 31, 2012 9:21 am 
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Acharya wrote:
Excellent. Thank you for taking the time to post all that.


Thanks. It is all really interesting in exploring the foundations of astrotheology.

Early Babylonian Astronomy

This chapter covers the period up to about 500 BC, showing they had a surprisingly exact understanding of empirical prediction.

Mesopotamia was a cradle of civilization and trade, with surplus enabling scholarly professionals to focus on astronomy, and invention of writing enabling recording of commercial transactions, tax, myth and astronomical observations. O'Neil says all the Greek zodiac names began in Babylonian times. Already in the second millennium BC, there are records of decanate stars, one for each ten days of the year. The position of the sun was marked over three seasons - the hot and dry months of Enlil, the stormy and windy months of Anu, and the cold wet months of Ea. Sumerian names have survived for 407 celestial objects, including 341 individual stars.

Tablets survive of very early dates of visibility of Venus, indicating accurate knowledge of the 584 day Venus period. O'Neil comments "this is a remarkable piece of early astronomical observation carried out probably in the seventeenth or sixteenth century BC. It would be surprising if it were unique in its own time, more likely it is unique in its survival and recovery." (24)

Ptolemy, writing in the second century AD, claimed to have Babylonian eclipse records from 747 BC. Records indicate accurate predictive knowledge from this early time, including eclipses and retrograde motion of planets against reference stars. Meticulous diaries enabled prediction of planetary positions based on repetitions over decades and centuries. It appears the Babylonians discovered the Saros eclipse cycle of 223 months by the 6th century BC. This period is the conjunction of the three lunar months, synodic, draconic and anomalistic, discussed above, and its discovery is a remarkable achievement, showing the reverence they obviously had for precise observation of the heavens.

O'Neil notes that "it is a matter of some puzzlement how the Babylonian astronomers in their earlier phase discovered the eclipse cycle." He speculates that observation over centuries would have enabled prediction of eclipses occurring below the horizon, using purely empirical methods. The early diaries show these accurate early eclipse records were of predictions, not just observations.


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PostPosted: Thu Nov 08, 2012 8:07 am 
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Late Babylonian Astronomy
The diaries of Babylonian astronomers recorded observations of the sun, moon and planets over hundreds and perhaps thousands of years, enabling accurate comparison of cycles to predict future locations and dates of celestial events. Every month, records were kept, and many of these have survived on clay tablets, showing the length of the month (29 or 30 days), details of the rising and setting times of the sun and moon and planets, eclipses both observed and calculated, planetary signs and reversals of direction, calculated dates of solstices and equinoxes (allegedly inaccurate), dates of lunar conjunction with reference stars and with planets, rain, crops and historical events such as the entry of Alexander the Great.

Using sophisticated mathematical techniques, the sexagesimal 60-based counting system enabled accurate astronomical calculation of quite obscure cosmic patterns such as the repetition of eclipse cycles every 18 years, now known as the Saros cycle. Ptolemy claimed to have detailed Babylonian star diaries going back a thousand years. Records of their 30° division of the path of the sun into our familiar twelve signs of the tropical zodiac date to five hundred years before Christ.

The Babylonian seers divided the 360 degrees of the circle by sixty into minutes, by sixty again into seconds, and by sixty again into thirds, providing extremely accurate data. Unusually, the distance of the moon from the ecliptic was measured in units of fifty seconds, one 72th of a degree (a unit providing the time period known as the barleycorn, or Jewish Chelek). The Babylonians understood the difference between the synodic, draconic and anomalistic months, as the basis of the prediction of eclipses both seen and unseen. O’Neil says the Babylonians had ‘amazing precision’ in their data, for example accurately calculating the averge length of the synodic month (sun-moon conjunction) to within 9 seconds of the accurate period, an error of three parts per million. We apparently have about 300 surviving Babylonian ephemerides, of various length and completeness, in addition to diaries and almanacs.

Despite all this evidence of accurate measurement over centuries of the position of the sun and moon and planets against the fixed stars, O’Neil follows Neugebauer in asserting that the Babylonians were entirely unaware of precession of the equinox. I find this completely implausible, including for the following reasons.

The Babylonians' intense focus on accurate observation and recording of the position of the moon included reference against the background stars. Their level of accuracy was such that records of lunar eclipse would have shown precession within decades. But they did not just keep these records for decades, they kept them for centuries, with historical records available to Ptolemy over a thousand years. So, we are asked to believe that the Babylonians knew when and where eclipses would happen, and recorded their position against the stars, but completely failed to notice that these regular events were slipping around the circle at a steady rate with respect to the annual cycle of the seasons.

Further, we can ask why the Babylonians chose counting systems which precisely mesh with the traditional reasonably accurate (error 0.6%) belief that the sun precesses by one degree every 72 years. This rate means precession through a zodiac sign takes 2160 years or 6x6x6x10. It is a sexagesimal number, which provides the slow basis upon which shorter sixty based periods of hours, minutes and seconds almost certainly were based.

Next, why did they measure the position of the moon in 50 second divisions? This barleycorn distance is how far the sun precesses in a year. So eclipses, which indicate the exact position of the sun and moon against the stars, provide a ready means to observe precession, with the position varying by one barleycorn per year. I have discussed this topic further in the thread Precession of the Moon and Christian Theology.

What it all means is that the calculated position of the moon at lunar eclipses provided an obvious indication of precession, measured by this fifty second distance each year. The eclipse position of the moon against the background stars precesses over one Saros cycle of 18 years by an average of 18 barleycorns, one quarter of a degree, exactly half a lunar diameter.

There really is a strong implausibility in Neugebauer's argument that among all their detailed accurate stellar diaries and calculations and predictions, the Babylonians knew exactly when lunar eclipses would happen, even those they could not see, and they knew exactly where they would happen against the background stars to accuracy of the minute or even second of arc, and they knew that each eclipse was part of a family of 18 years duration based on the conjunction of three monthly periods, and they used this knowledge as a central part of their culture for a thousand years, but they somehow did not notice the precession which pulls all this data together into a coherent system and located each Saros eclipse return at a steadily earlier position on the ecliptic, despite these facts being obvious from their long records which were at the centre of their religion.

The Babylonian main unit of lunar location measurement was precisely the amount of solar precession in a year. It makes sense that the Babylonians chose this measurement interval because it accurately describes the main orbital period of the earth that measures the steady observed movement of the stars over centuries by precession.

The Jews learned much of their astronomy during the exile in Babylon in the sixth century BC. One of the texts that drew on this experience is the book of the prophet Ezekiel, which claims to have been written in Babylon, in this star-worshipping culture. In his first chapter, Ezekiel explains the framework of his prophecy against clear precessional motifs, motifs which accurately predict the movement of the heavens. The four living creatures are the main stars marking the four seasons. The wheels within wheels are the circles seen in the sky of the zodiac and the Milky Way, with the inner wheel of the position of the sun against the seasons slowly moving against the stable outer wheel of the stars. Although the Jews rejected worship of nature, it seems they took they understanding of prophecy from this rejected method.

A main Babylonian myth, the epic of Gilgamesh, incorporates the annual measure of precession of fifty seconds. The Argo, Gilgamesh's boat, also later used by Noah and Jason, has fifty rowers, one for each second of precession of the sun against the stars each year. Viewed from Babylon, this fifty second distance is how far the great ship of the night sky, the Argo, advances across the southern horizon each year.


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PostPosted: Thu Nov 08, 2012 1:45 pm 
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Very interesting 8)

Good work, Robert

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2013 Astrotheology Calendar
The Mythicist Position
Christ in Egypt: The Horus-Jesus Connection
Stellar House Publishing at Youtube


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PostPosted: Thu Nov 15, 2012 6:28 am 
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Early Greek Astronomy

This chapter starts by citing Works and Days by Hesiod, reputedly dating to the 8th century BC, who marked the seasons for harvesting and planting by the heliacal rising and setting of the Pleiades. This is an event that changes by a day every lifetime, and would presumably have been a record of a much older oral tradition. Like Homer, Hesiod documented early Greek oral tradition, including the idea of a descent of ages from gold through silver and bronze to iron. This idea, which must have been old by the time it was written down, comes from the ancient Indian tradition of the Yugas, helping to show the links between ancient myths. Hesiod's comment about the Pleiades is interesting from a precessional viewpoint, since the observed heliacal date against the seasons changed steadily through the centuries, and much faster than the date changed for Sirius, due to their relative positions in the sky. Even if precession was not documented, and its scientific basis was not understood, it must have been observed in such oral farming cultures, given the use of the Pleiades first visibility in the morning sky as a marker for the date of harvest.

Early Greek philosophers had a range of speculative ideas about the nature of the universe. Thales in the sixth century managed to predict the total solar eclipse during a battle on 28 May 585 BC. Herodotus says “it happened that when the fighting had been joined, day suddenly became night. A prediction that this inversion of the day was going to happen, was made publically by Thales of Miletus in announcements to the Ionian people; he proposed exactly the same period favorable for it as the one in which the omen actually occurred.” O’Neil speculates about whether Thales obtained his prediction from older Babylonian records, a very interesting question in the context of the widespread view of the Greeks as the founders of science.

Early Greek philosopher/scientists were backward compared to the Babylonians, holding to flat earth theories and other wildly incorrect ideas. Pythagoras, who reputedly learned philosophy in Egypt in the 6th century BC, helped start the move away from ignorance, due to his focus on numbers. However, as O’Neil points out, “the Pythagoreans became increasingly mystical and secretive. As a consequence of their keeping their views to themselves, few of their doctrines became public. They may have extended their numerical analyses to astronomical matters but we have little information on that. They do seem to have asserted the sphericity of the Earth.” It is important to ask why this group would have been secretive. It is likely their scientific ideas were not comprehended by the general public, and they therefore found discretion the better part of valour. The position of Pythagoras shows that study of numbers was considered esoteric, and suggests there was a lot of work on related topics that was kept secret.

Parmenides is the next philosopher mentioned. His distinction between reality and appearance was enormously influential, especially on Plato. He held the earth to be spherical, within a spherical universe, and reputedly understood Venus as both morning and evening star. Plato helped to develop Parmenides’ ideas, stressing the need to mathematize astronomy. O’Neil does not mention Plato’s main astronomical text, the Timaeus, which includes a cryptic reference to the relation between the changing zodiac and the unchanging galaxy, the idea at the origin of the Christian Chi-Rho cross. Timaeus also gets a cryptic mention in the Bible, in the beggar Bartimaeus at Mark 10:46.

Plato may have strongly influenced the wild goose chase of Ptolemaic astronomy, with an insistence that the heavens must be perfect spheres, an idea formulated further by Eudoxos soon after Plato. Aristotle developed this theory of the crystalline spheres with ideas about gearing of extra small spheres, as they struggled to fit the observations into a geocentric model. We will come later to Ptolemy’s theories on this topic, including the crank, a wrong idea with an unfortunate subsequent history.

The Metonic lunar cycle was documented in Greece in the fifth century BC. This nineteen year period measures the recurrence of the phases of the moon against the seasons. Again, it seems to have been discovered in Babylon before Meton. The Metonic cycle may well be another pointer to early knowledge of precession, like the eighteen year Saros cycle of eclipses, since the recurrence of lunar position after nineteen years involves precession by about half a moon width, a measurable observation by ancient methods.

The Greeks also discovered in the fifth century BC that the seasons are not of equal length, due to the change in apparent speed of the motion of the sun. O’Neil claims the Babylonians were not aware of this fact. This is a topic explored more fully in the later work of Hipparchos, using measuring devices such as the armillary sphere, to be discussed in a later post. O’Neil makes a surprising, and certainly wrong comment, that the Greeks at this time had no method to establish due east. Leaving aside the fact that the Egyptians had established the cardinal points thousands of years ago to extreme level of accuracy with the alignment of the Great Pyramid, it is simple to determine the directions by observing the celestial pole, which is always due north. Contrary to O’Neil’s claim, a compass is not needed to work out directions.

In the 3rd century BC, Aristarchos posited the rotation of the earth and tried to estimate the distance to the moon and sun using trigonometry, and Eratosthenes tried to measure the circumference of the earth by measuring the angle of the sun at midday in different latitudes in Egypt. Many of these ideas are only known by brief references in later writers, illustrating how much of the development of astronomy has been lost by the combined indifference and stupidity of later times.


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