Ancient Astronomy (Part 1)

At the planetarium it is often stated that every time you look into the sky you are doing astronomy, it has become a slight mantra that we chant to encourage people to gaze up at the visible universe and really grasp that astronomy and space is truly all around us. But when you look up to your favourite planet or constellation, you are not only practising astronomy but also looking at its history.

The knowledge we have of space and the universe is something that has been the product of our ancestors reaching many thousands of years back. As Isaac Newton famously said, ‘If I have seen further than certain other men, it is by standing on the shoulders of giants.’ These ‘giants’ have paved the way throughout the centuries and even millennia to help successive cultures and eras to expand on their knowledge of space and astronomy. Even our modern day practices of astronomy and space still rely on and use fundamental information that was produced in those premature days of ancient astronomy. So let’s take a deep look back to the beginnings of our stellar knowledge and really see how even the basic methods and ideas provided the foothold to our knowledge of the Universe.

A list of Sumerian deities in Cuneiform 2400BC

A list of Sumerian deities in Cuneiform c2400BC



If you have ever tried to trace the history of ancient astronomy you probably have same across many different cultures and practices and gotten quite confused so hopefully I can simplify the cacophony of information out there regarding this topic. When I sat down to truly discover who really began the practice of astronomy I believed I would be stating that the Babylonians would be the answer but alas I was wrong. The people of Babylon gave the science of astronomy many things but they essentially where not the source. It was a close neighbouring civilisation of the Babylonians that can really take much of the credit for the beginnings of our stellar wanderlust, the Sumerians. Some historians tend to merge the astronomical history of the Babylonians and Sumerians together which therefore leads to some confusion about the two cultures but I believe the Sumerians deserve the accurate recording of their achievements.

The Sumerians were the people of the ancient city of Sumer, which was in the south-most region of the ancient Mesopotamia, a region that covers multiple countries of today’s modern map, including Iraq, Kuwait and parts of Syria, Iran and Turkey. It is regarded by many as the “Cradle of Civilisation” due to its contributions to the world. The name Sumer even translates to “Land of the Civilised Kings.’ The repeated connotations of civilised with reference to the Sumerians seems rightly deserved as they are who we believe gave us the written word! Maybe not as we see it today but they developed a system that was be the stem of recording information and ideas. It is called cuneiform and it is dated as far back as 3500—3200 BC. Some may question how this is directly linked to astronomy but how we could record our findings for our successors if there was nothing to show what we did?  But this was not their only contribution. We hear many myths regarding ancient gods and heroes, in particular with constellations and these date as far back as the Sumerians who practised astrolatry, which required them to worship the stars and other astronomical objects as various gods in their massive purpose-built temples called ziggurats. On top of the ziggurat was a shrine where these astrological priests would perform rituals including the animal sacrifices that has took place in many faiths, religions and cultures.

Ancient_ziggurat_at_Ali_Air_Base_Iraq_ -WIKI

Ancient ziggurat at Ali Air Base in Iraq (image credit: via



This relationship between the worship of various deities and stars filtered through different cultures throughout the years and it does get quite confusing as many different cultures adjusted these gods to suit their own faiths and mythologies. One of the final offerings that the Sumerians gave to astronomy that is still widely used today is the use of a sexagesimal (base 60) place-value number system. A modified system of this is still used today to measure things such as time, angles and geographic coordinates. This gave a system for recording the various star and planetary locations for both themselves and their astronomical successors.

One of the most famous cultures with regards to astronomy and a place that has been credited with many of the astronomical firsts that really belonged to the Sumerians was the other Mesopotamian region of Babylon! Although the Babylonians may not have been the source of many of these astronomical practices that the Sumerians formed, they did perfect them as best they could and became a true fountain of knowledge when it came to astronomy. Babylon (in modern day Iraq) truly took the practices of Sumerians and made them their own and created a vast library of information and records that still to this day help astronomers to look to events that have happened in the past and even help in the predictions of astronomical events in the future.  Ancient Babylonian priests observed the movements of the stars and planets in vast detail and used these recorded movements and information to predict events, which they referred to as omens. This was not just a case of recording details every other day or week but consistent daily, monthly and yearly records. Although they approached the data with a philosophy and beliefs which seem quaint to us they essentially got many predictions of planetary movements right based on prior observations. This meant they were immensely successful and even kings sought their advice to help predict future events. This method of consistent observation and recording would become an astronomical base that would be expanded upon by many other cultures in the future, including the Greeks. Even though observing and recording may be viewed as quite a simple practice, many scholars refer to this method as being the first scientific revolution.

The Babylonians where the first to have a functioning knowledge of planetary theory and to recognise that they are periodic, (hence all their awesome predictions) and became the first to apply mathematics to their predictions.  It is thanks to their detailed records using cuneiform on tablets that we have so much information about the history of their culture.  These remains are fragmented as these have been in circulation for over 2000 years so there have been some casualties and wear and tear but enough has survived for us to derive the vital information about this learned culture. These tablets where called ‘Enuma Anu Enil’ which translates to ‘In the days of Anu and Elil’.  Anu was regarded as the God of Heaven and the King of Gods; of the Sky and of Spirits and demons and Enlil was regarded as the God of Wind and Storms. There were many others and these tablets formed the source of many of their omens given to Kings.

A big issue that the Babylonians wanted to fix was the problem of having an accurate calendar. This gave them more reason to focus on the motions of the Sun and Moon and this observation gave successive cultures and even modern day astronomers a good basis of information to follow.

Although the methodology of the Babylonians was using the naked eye to make their observations they did use tools to help them. One of the oldest recorded astronomical tools was the sundial or shadow clock. The definitive history of these day measuring instruments is quite sketchy with a belief that they were used before there were any official records of them. They were quite a simple tool in that they used the position of the sun to create a shadow that told the hours of the day and they have been created in many cultures and are still used today in many places. They are also sometimes confused with the Egyptian Obelisks, a long pillar that was erected in a temple to commemorate the pharaoh it was commission for, but their shadows did allow people to tell the hour of day.

Greek waterclock similar apparatus to the Babylonian water clock although none survived from the Babylonian period. - WIKI

Greek waterclock, a similar apparatus to the Babylonian water clock, unfortunately none survived from the Babylonian period.  (image credit:


They did not just rely on sundials; they also used another extremely old astronomical tool of a water clock. Time was measured using a water clock by regulating the flow of a liquid in or out of a vessel which is then measured. They used these simple contraptions to aid their astronomical calculations as far back as 2000 BC although none of their versions survived and we just know of their existence and use from their clay tablet recordings.

For anyone also who has a strong belief in astrology you will find you have the Babylonians to thank for their existence and also the Sumerians.  As they watched the planets and sun in the night sky they noticed that they almost always travelled the same path across the sky throughout the year and therefore through certain patterns or constellations that they had noted in the sky. This is what became known as the signs of the zodiac and they relied on them for many of their omens and predictions and like some people today, they also used them to try and define peoples characteristics or personality due to the constellation that Sun was in when a person was born.

When you research Babylonian astronomy it is difficult to pull yourself away as there truly is so much credited to the scholarly culture and they really can be credited with laying the foundation of western astronomy but there are more to note and I only have so many words!

Great Pyramid of Giza - Oldest and largest of the pyrimids and holds much astronomical significance - WIKI

Great Pyramid of Giza: oldest and largest of the pyramids and holds much astronomical significance (image credit:


In this analysis of the history of ancient astronomy I could not go on without referring to the Egyptians and their astronomical culture. With so much research into the history of Egyptian astronomy it has been noted that it dates as far back as 5000 BC with the discovery of the stone circles of Nabta Playa, a prehistoric calendar that marked the important summer solstice. The Egyptians, like the Babylonians and Sumerians held vast importance in the stars, constellations, Sun and planets and used them in various ways such as predictions or omens and for practical uses in agriculture and navigation. We cannot say the Egyptians just ‘dabbled’ in astronomy as much of their lives and infrastructure has astronomy and the stars permeating through them. An obvious piece of structural proof was that the four corners of most of the pyramids lined up with north, south, east and west. And this is just the beginning of the link between astronomy and the pyramids. Many of the Egyptian temples and pyramids are claimed to have been built in correlation to the stars, specifically the three stars of Orion’s Belt and the bright ‘Dog Star’ Sirius which held great significance to the ancient Egyptians. The Egyptian pyramids also were built so that the light of the Sun could only enter once a year, obviously planned and not accidental.

A huge occurrence that the Egyptian culture focused around was the yearly flooding of their sacred river, the Nile. This provided rich soil for agriculture and therefore was very important. The Egyptian astronomers or priests realise a correlation between the yearly flooding and the summer solstice and the heliacal rising of Sirius (when the star rose above the horizon before the Sun). These astronomical priests were able to predict the flooding and therefore became very powerful people in Egyptian society. This worked well alongside certain constellations appearing before and after the flooding to allow the harvesting and planting of crops.

image of sirius by HST

Sirius A_and B The ‘Dog Star’ had vast importance to Egyptians. Image credit NASA, ESA H.Bond (STScl) and M.Barstow (University of Leicester))



So it is obvious they relied heavily on similar methods to those of the Sumerians and Babylonians to consistently observe and record the motions and events of the stars, planets and constellations to create a calendar (or multiple calendars in the Egyptians case), so that they could predict events and help with their day to day lives. They also placed a strong significance on and belief in the Sun and on the horizon. Their most revered god was Amon-Ra who they believed held the power of the Sun and depending on it’s different positions in the sky, the Sun would also represent different gods, from the rising Sun representing Horus the ‘sky’ god to the setting Sun representing Atum, the ‘creator’ god. Although their first calendar was based on the moon they evolved to create and use a solar calendar. Their regular recording meant that they knew the year was roughly 365 days and they were similar to us and divided their year in 12 monthly periods that where made up of approximately 30 days. The tools they used were similar to the Sumerians and Babylonians, such as the sundial or obelisk mentioned earlier to help note the hours or periods of the day which divided the day into 24 hours.  They also used star clocks to help determine the time by measuring the Plough’s (or Big Dippler’s) position in the sky and used simple mathematics to work out the time. So it’s quite humbling to realise how such modern techniques really aren’t that modern!

Heliopolis Ancient Egyptain Obelisk dated roughly 1900 BC - WIKI

Ancient Egyptian obelisk dated roughly 1900 BC  (image credit:


Again the Egyptians are truly fascinating and there is so much astronomy running through their religious practices and beliefs as well as their practical everyday lives and infrastructure that it would be easy to say that without their realisation and practice of astronomy the ancient Egyptian culture would have been vastly different than what it was.

It is quite fascinating that when I started to research the topic of ancient astronomy I believed I could fit all my findings into one concise article but alas I have failed, greatly! There is so much to be found in each of the ancient astronomical cultures that cannot be omitted from my findings. So what began as a singleton article will now hopefully develop into a trilogy of the ancient astronomical cultures and the daunting task of trying to decipher through the uncertain findings and give credit of astronomical firsts where they are truly due.

(Article by Kerry Scullion, Education Support Officer)