You updated your password.

Reset Password

Enter the email address you used to create your account. We will email you instructions on how to reset your password.

Forgot Your Email Address? Contact Us

Reset Your Password


The Remarkable Science of Ancient Astronomy

Discover the ancient sky with an award-winning teacher and noted astronomer.
The Remarkable Science of Ancient Astronomy is rated 3.9 out of 5 by 70.
  • y_2024, m_7, d_23, h_8
  • bvseo_bulk, prod_bvrr, vn_bulk_3.0.42
  • cp_1, bvpage1
  • co_hasreviews, tv_4, tr_66
  • loc_en_CA, sid_1866, prod, sort_[SortEntry(order=SUBMISSION_TIME, direction=DESCENDING)]
  • clientName_teachco
  • bvseo_sdk, p_sdk, 3.2.1
  • CLOUD, getAggregateRating, 11.52ms
Rated 4 out of 5 by from The lectures have somewhat variable value. This is a really hard Course to review. The lecturer’s presentation is clear and precise, and he has useful images to accompany his words. He is careful to differentiate what is capable of being substantiated from conjecture. Yet, at the end of each lecture I felt marginally deflated. Perhaps this was because I am acquainted with the history of many cultures and civilisations, and this Course did not reveal many new nuances. Lecture 6 is a special enigma. Why not place this wide-ranging discussion at the beginning of the series ? And his assertion that the ancient Greeks thought the Earth was flat is just ludicrous. The idea of a spherical Earth was floated by Pythagoras around 500 BC and validated by Aristotle a couple centuries later. Eratosthenes, around 200 BC used his observations of two vertical sticks at noon in Alexandria and Syene to estimate the circumference of the entire planet. Since the difference in shadow length is 7 degrees in Alexandria and Syene, that means the two cities are 7 degrees apart on Earth’s 360-degrees surface. Eratosthenes hired a man to pace the distance between the two cities, and learned that they were 5,000 stadia apart, which is about 800 kilometres. His answer was about 300 kilometres from the presently accepted view. I only mention this blatant error because it leaves me with an uneasy feeling about the rest of BS’s comments. However, if you know nothing about paleo astronomy then this is a good Course to start your learning.
Date published: 2023-11-02
Rated 5 out of 5 by from A Unique Presentation Let's get this out of the way first: the instructor has a theatrical style of presentation that may take some getting used to. I got used to it and greatly enjoyed the course. There is clearly a lot of personal interest involved in Prof. Shaefer's choice of subject matter, and it is partly an account of his own extensive original research achievements. Once we understand the lay of the land, this course is excellent and highly informative. The biggest take-home lesson for me was that ancient Babylonians, ancient Greeks, and other people in times long past were carefully collecting observational data that stand up to scrutiny today! Shaefer has even used these data in various ways, such as the variation of the length of the day over 2500 years. It was also enlightening to see how the smartest of the Greeks had already figured out that the earth was round and revolved around the sun; too bad the majority didn't want to let go of the notion that the earth was central to the universe. Shaefer's description of navigation by the stars leads clearly to how modern gps systems work, so the ancients used pretty much the same geometrical approach without electronics. One of the cardinal points of the course is that an understanding of solid geometry will take you a very long way toward understanding a collection of spheres moving around in space. It is remarkable how much scientific information can be derived without the actual employment of what we today consider to be science. Very interesting!
Date published: 2023-08-29
Rated 1 out of 5 by from Chaldean Astronomy What an Ancient Astronomy course if nothing about Chaldean/ Babylonian discoveries? I think the Author is joking!
Date published: 2023-05-20
Rated 3 out of 5 by from Mixed feelings I've watched these lectures at least twice -- some more than that -- and I have to confess that I'm still not sure what to make of the course. I suppose the problem is that it wasn't really what I expected. I think what I expected was a detailed explanation of how astronomy developed in the ancient world, and how we came to know the things we did. I'm always impressed by how much our ancient forebears were able to find out, without access to modern technology (apart from the flying sources, of course ;) ), I though that I would understand astronomy better if I could see how it developed as a science over the years. However, I found that I failed to undestand a lot of the material that was presented. I get the impression that the intended audience was really people who knew about astronomy, and wanted to learn some history. I know little about either subject, so perhaps that's why it didn't really sink in. I'm not saying that the lectures weren't interesting -- they were; rather, I didn't learn what I was hoping to learn.
Date published: 2022-09-15
Rated 3 out of 5 by from Moderately Useful I learned a decent amount about ancient astronomy, but not as much as I had hoped. The lectures are not well organized--there's a lot of repetition--and some basic astronomy concepts are not clearly defined or explained. And the professor's manner comes across as too dramatic at times.
Date published: 2022-07-02
Rated 3 out of 5 by from the remarkable science of ancient astronomy i enjoyed the class and enjoyed the presentation by the professor. my only problem with the course was that i really didn't understand the astronomy parts such as the ecliptic,precession etc. and i was totally lost when he described how any of the devices that the ancient astronomers worked. i am going to have to research those subjects further.
Date published: 2021-11-06
Rated 3 out of 5 by from Disappointing The lecturer did not seem to know who his audience was. One the one hand he presented information as if he were speaking to eight graders in a fakey dramatic voice and two sentences later he was using jargon understandable to those who already knew something about basic astronomy. In all the course I have taken from Great Courses this is the only time I have encountered a presenter who spoke so much about his accomplishments.
Date published: 2021-07-20
Rated 3 out of 5 by from A little disappointing I read the reviews before buying it and I have to agree there is too much time spent on the lecturer's own research. On the whole, I really didn't learn as much as I hoped and still don't understand what an elliptical is. But I still would recommend it to those who want a generalized overview
Date published: 2021-06-21
  • y_2024, m_7, d_23, h_8
  • bvseo_bulk, prod_bvrr, vn_bulk_3.0.42
  • cp_1, bvpage1
  • co_hasreviews, tv_4, tr_66
  • loc_en_CA, sid_1866, prod, sort_[SortEntry(order=SUBMISSION_TIME, direction=DESCENDING)]
  • clientName_teachco
  • bvseo_sdk, p_sdk, 3.2.1
  • CLOUD, getReviews, 3.94ms


Taught by Professor Bradley Schaefer of Louisiana State University, this course shows how ancient Egyptians, Greeks, Indians, Chinese, and other cultures saw the sky. You learn how the Sun, Moon, and stars were their clock, calendar, and compass; constellations encoded their mythologies; and the perfection of the heavens inspired religious and philosophical ideas, ultimately laying the foundation for modern science.


Bradley E. Schaefer

In olden times, everyone lived in close contact with the skies, so the kings and common folk would appreciate the many practical, symbolic, and philosophical applications of ancient astronomy.


Louisiana State University
Bradley E. Schaefer is Distinguished Professor and Alumni Professor in the Department of Physics and Astronomy at Louisiana State University (LSU). He earned his undergraduate and Ph.D. degrees in Physics, both from the Massachusetts Institute of Technology. He was a research astrophysicist at NASA's Goddard Space Flight Center and a professor at Yale University, before joining LSU, where his teaching has earned him the Alumni Professorship and the Distinguished Faculty Award. He has over 200 publications in refereed journals. Starting in the mid-1990s, Professor Schaefer joined the Supernova Cosmology Project, led by Saul Perlmutter. This group found that the expansion rate of the universe is accelerating, propelled by an unknown dark energy. As one of the discoverers of dark energy, Professor Schaefer received a share of the Gruber Cosmology Prize in 2007 as well as a share of the Breakthrough Prize in Fundamental Physics in 2015. In 2011, Perlmutter was a co-winner of the Nobel Prize in Physics for leading this work. In addition to his cosmology research, Professor Schaefer has written numerous articles on the history of astronomy, including frequent pieces for Sky & Telescope. He is on the editorial boards of both Archaeoastronomy and the Journal for the History of Astronomy, and he has served on the editorial board for Culture and Cosmos.

By This Professor

The Remarkable Science of Ancient Astronomy
The Remarkable Science of Ancient Astronomy


Stonehenge and Archaeoastronomy

01: Stonehenge and Archaeoastronomy

Why were the motions of the Sun, Moon, and stars so important to ancient people? Investigate key astronomical directions noticed by all cultures. Then embark on your study of Stonehenge, seeing how it gave birth to the field of archaeoastronomy and to some very curious modern theories....

31 min
The Real Stonehenge

02: The Real Stonehenge

In the popular mind, Stonehenge was built as a sophisticated astronomical calculator presided over by priestly astronomers called Druids. But is this view dating from the mid-1960s correct? Address the evidence, and survey the archaeological record to discover the most probable function of Stonehenge....

30 min
Alignments at Maes Howe and Newgrange

03: Alignments at Maes Howe and Newgrange

Explore Neolithic tombs and monuments across Europe, discovering an array of alignments toward astronomical events. Start with two sites that are similar to Stonehenge in their clear orientation to the winter solstice: Maes Howe in the Orkney Islands, and Newgrange in Ireland....

29 min
Astronomy of Egypt's Great Pyramid

04: Astronomy of Egypt's Great Pyramid

Study the astronomical significance of Egypt's Great Pyramid. How did its builders achieve such phenomenal accuracy in the pyramid's alignment to the cardinal directions? Were its air shafts intended to point at stars of special importance? Also evaluate modern claims for the mystical power of pyramids....

29 min
Chaco Canyon and Anasazi Astronomy

05: Chaco Canyon and Anasazi Astronomy

Travel to Chaco Canyon, New Mexico, where the Anasazi culture practiced sky-centered rituals a thousand years ago. Look for evidence of their astronomical knowledge, examine their many "sun daggers," and probe the controversial pictograph thought to depict the Crab Nebula supernova explosion in 1054 AD....

28 min
Ancient Cosmologies and Worldviews

06: Ancient Cosmologies and Worldviews

Consider the astronomy-based world views of different ancient cultures and how they answered the three big questions: Where did the world come from? What is the nature of the universe? What is its fate? Survey the beliefs of the Greeks, Chinese, Australian aborigines, and other groups, seeking common elements....

29 min
Meteorite Worship and Start of the Iron Age

07: Meteorite Worship and Start of the Iron Age

Witnessing a meteor fall must have been a strange and awe-inspiring experience for people long ago. Travel around the world to places where meteorites were worshiped and also used as a source of iron, which was rarer than gold before the smelting technology of the Iron Age....

30 min
Eclipses, Comets, and Omens

08: Eclipses, Comets, and Omens

Since no human can touch the sky, any unexpected celestial event must be a divine omen. Reenter this primordial state of mind, seeing eclipses and comets the way they were perceived before the advent of modern science. In the course of this investigation, discover why comets became more feared than eclipses....

29 min
The Star of Bethlehem

09: The Star of Bethlehem

For centuries, astronomers have struggled to find an explanation for the Star of Bethlehem, recounted in the Gospel of Matthew. Professor Schaefer focuses on a recent theory that has taken scientists and biblical scholars by surprise, due to its success at solving problems that plagued all previous proposals....

29 min
Origins of Western Constellations

10: Origins of Western Constellations

The human propensity for pattern recognition and storytelling has led every culture to invent constellations. Trace the birth of the star groups known in the West, many of which originated in ancient Mesopotamia. At least one constellation is almost certainly more than 14,000 years old and may be humanity's oldest surviving creative work....

32 min
Chinese and Other Non-Western Constellations

11: Chinese and Other Non-Western Constellations

Study the constellation patterns of ancient China, which influenced those of India and Arabia. Professor Schaefer dates the origin of the Chinese star groups called lunar lodges, and he samples southern constellations conceived by cultures in South America, and Australia....

30 min
Origins and Influence of Astrology

12: Origins and Influence of Astrology

Astrology grew up hand in hand with astronomy. Focus on the different astrological traditions in Mesopotamia, China, India, and Mexico. Also trace the spread of astrology through the Mediterranean world. As an example, study the auspicious horoscope of Octavian, who became Emperor Augustus....

31 min
Tracking Planet Positions and Conjunctions

13: Tracking Planet Positions and Conjunctions

Until the invention of the telescope in 1610, astronomy was mostly the study of the sky positions of the Sun, Moon, and planets. Learn the extraordinary precision attained by ancient astronomers in their observations. Discover why they prized this knowledge, and also uncover a lost great discovery of the Babylonians....

31 min
Ancient Timekeeping and Calendars

14: Ancient Timekeeping and Calendars

For ancient people, keeping track of the time of day and year required a detailed understanding of the motions of the Sun, Moon, and stars. See how different cultures solved this problem. Also learn how to use a handy astronomical measuring device called the astrolabe....

31 min
The Lunar Crescent and the Islamic Calendar

15: The Lunar Crescent and the Islamic Calendar

Delve into the surprisingly tricky problem of deciding when a lunar month begins-usually determined by the first sighting of a crescent Moon after new Moon. Professor Schaefer describes his algorithm for calculating this event and then applies it to dating the crucifixion of Jesus....

29 min
Ancient Navigation: Polynesian to Viking

16: Ancient Navigation: Polynesian to Viking

In the era before compasses and GPS, precise direction-finding was possible only through knowledge of the sky. Learn how the Polynesians found islands across thousands of miles of open ocean, and how the Vikings solved the very different challenge of navigating the North Atlantic....

29 min
Breakthroughs of Early Greek Astronomy

17: Breakthroughs of Early Greek Astronomy

Between 600 and 200 BC, Greek astronomers went from being flat-Earthers to full proto-scientists with reasonable models and distances for the Solar System. How and why did this revolution happen? Focus on the achievements of Thales, Aristarchus, Eratosthenes, and Aristotle....

31 min
The Genius of Hipparchus

18: The Genius of Hipparchus

Considered the greatest astronomer of the ancient world, Hipparchus created a thousand-star catalog and discovered precession, the eons-slow rotation of the fixed stars around the ecliptic. Did this remarkable discovery give birth to the Mithraic religion, which rivaled Christianity?...

31 min
Revealing the Antikythera Mechanism

19: Revealing the Antikythera Mechanism

In 1901, divers off a Greek island discovered a corroded bronze artifact composed of interlocking gears. Later analysis and X-ray imaging show it is an astonishingly versatile astronomical computer. Professor Schaefer identifies a probable date when it was built and two likely candidates for its brilliant designer....

29 min
How the Antikythera Mechanism Worked

20: How the Antikythera Mechanism Worked

Learn to operate the Antikythera mechanism, the glory of ancient astronomy. Modern models show how a simple turn of the crank could reveal the day of the year, phase of the Moon, possible eclipse dates, the cycles of ancient games, and other information. Probe the historical impact of this device....

28 min
Achievements and Legacy of Ptolemy

21: Achievements and Legacy of Ptolemy

Ptolemy has been called the greatest astronomer of antiquity. But was he? Evaluate his reputation by focusing on his star catalog, celestial coordinate system, and magnitude scale. Then gauge the extent of his influence over later astronomers, which lasted over a thousand years....

30 min
Star Catalogs from around the World

22: Star Catalogs from around the World

The genius of Greek astronomy is epitomized by the star catalogs of Hipparchus and Ptolemy. Professor Schaefer recounts his exciting discovery of a star chart apparently influenced by Hipparchus's lost catalog. Close by comparing Greek star catalogs with those of China and the Arab world....

30 min
How Ancient Astronomy Ended

23: How Ancient Astronomy Ended

Review the state of astronomy in 1500. Then chart the revolution sparked by Copernicus's heliocentric theory of the Sun and planets. Learn how Copernicus was the last of the ancient astronomers, succeeded by the founders of modern science, including Tycho, Kepler, and Galileo....

30 min
Ancient Astronomy and Modern Astrophysics

24: Ancient Astronomy and Modern Astrophysics

Finish the course by seeing how ancient records of eclipses and supernova explosions have refined our modern understanding of Earth-Moon dynamics and stellar processes-proving that today's cutting-edge astrophysicists owe a great debt to astronomers who watched the skies long ago....

32 min