Nabta Playa Circle Tracks the Meridian Star
[Disclaimer: The contents of this post are merely the reflections of the author’s opinions an beliefs, the subject matter holds no scientific weight. The aim is to explore alternative views on history.]
Nabta Playa is a remarkable site composed of hundreds of prehistoric tumuli, stelae, and megalithic structures located in the Nubian Desert, approximately 100 kilometers west of Abu Simbel in southern Egypt. One of the most significant structures at Nabta Playa is a stone circle. Dating back at least 7,000 years, the stone circle is among the oldest of archeoastronomical devices.
The stone circle, which measures only four meters in diameter, is made up of a number of stones, including four pairs of larger stones, and then a series of smaller stones. In the centre of the circle are two rows of three stones. Two of the pairs align to form a north-south line, while the other two pairs form an east-west line. The east-west alignment is calculated to be where the sun would have risen and set from the summer solstice 6500 years ago.[1]
Wikipedia states that:
By the 5th millennium BC these peoples had fashioned what may be among the world’s earliest known archeoastronomical devices. These include alignments of stones that may have indicated the rising of certain stars and a “calendar circle” that indicates the approximate direction of summer solstice sunrise. “Calendar circle” may be a misnomer as the spaces between the pairs of stones in the gates are a bit too wide, and the distances between the gates are too short for accurate calendar measurements.[2]
It seems that present astroarcheologists have not figured out how to interpret the stone circle fully. This article will demonstrate how to the stone circle was possibly constructed by first using the rising sun on the autumnal equinox and finally the midnight ecliptic path on the autumnal equinox. The circle’s purpose might have been to track the stars that lie on the winter solstice’s midnight meridian, in order to find a ‘meridian star’.
Read more | The Meridian Star.
As mentioned above the stone circle has a peculiar setup where two lines of sight cross each other at a specific angle. One north-south line, the following the ecliptic at maximum tilt as illustrated in the image to the left.
The Nabta Playa stone circle is located on the Tropic of Cancer, therefore, therefore at specific times the ecliptic’s midheaven point falls together with the sky’s zenith point. When this happens the ecliptic is perfectly aligned to the east-west axis. This is fundamental for the construction of the circle.
The north-south line is naturally perpendicular to the east-west line, 90° from north. The marked east-west line runs at approximately 70° east from north.
At specific times the ecliptic’s midheaven point falls together with the sky’s zenith point… This is fundamental for the construction of the circle.
For the purpose of constructing the Nabta Playa stone circle the equinoctial days are calibrating days due to the equal division in the daylength. Because solstices are not equally divided they produce inaccurate angles.
On the autumnal equinox’s rising sun the Sun is announced by the ecliptic on an east-west line, with the midheaven coinciding to the sky’s zenith point. By understanding the significance the true north-south line is established. During the vernal equinox’s setting sun the ecliptic is slowly revealed after the Sun has already crossed the horizon. The former is preferred over the latter.
At midnight, on the autumnal equinox, the ecliptic path aligns to the east-west line 70° east from north, this is the ecliptic’s maximum tilt. On the vernal equinox the ecliptic path would have aligned 70° west from north, clearly this is not the line that was established.
Having established the two lines on the autumnal equinox using the rising sun and the midnight ecliptic path at midnight the Nubians can now anticipate the solstices. On the summer solstice the Sun rises approximately 70° East from north, and on the winter solstice the Sun sets 70° West from South.
N.B.
- The equinoctial days are for calibration
- The ‘solstices’ are for interpretation
It should go without saying that the process could have been done iteratively, finetuning the rock placements until the desired angles are achieved.
When we impose the astronomical events on the Nabta Playa stone circle we get the following schematic:
On the day of the winter solstice the Sun sets in the line of sight 70° west from south, at maximum tilt. That following night as the midheaven is raised to the sky’s zenith point, the ecliptic aligns east to west, 90° from north. However the solstices are not accurate during the rising and setting sun, especially at these latitudes, therefore it is very hard to precisely determine the day of the winter solstice. Instead the ecliptic’s midheaven-zenith point overlap was used during the winter period.
Because we already have the calibrated lines of sight we can easily find the target meridian on any winter night, see figure 5 below for a November 28th example.
Read more | Four Absolute Seasons.
This means that the ancient Nubians were able to find the winter solstice midnight meridian on any winter night. In the southern sky there are potential stars in the constellations of Carina and Vela the could be used as a Meridian Star for quite an extensive period. An example using the star Markeb (Vela) can be found here. N.B. looking south east you find the constellations Scorpius, Lupus, Centaurus and crux. They resemble a couple of elephants and a cross as depicted in an ancient Nubian graffito (c. 5000–3000 BCE) depicted below. [3]
It has been suggested that the three signature stones in the middle of the circle represent the three stars of Orion’s belt. This is fitting because it is the autumnal equinox that was used to calibrate the lines of sight. Furthermore, the constellation of Orion can be observed during the autumnal equinox’s midnight hour. For this one needs to stand at the northern gate while looking toward the southern sky, as can be seen in the image below. Note how the belt of Orion is similar to the lower row of stones in the middle of the circle of figure 2.
Moreover in 4461 BCE the Milky Way crosses the ecliptic, the celestial equator and the autumnal equinox’s prime meridian at midnight. Orion’s shoulder, Bellatrix, happens to align to this meridian. Tracking the autumnal meridian star equals winter solstice 6 p.m. (attention -4460–10–27 Julian equals -4460–09–22 Gregorian).
Key Points
Due to Nabta Playa’s location on the Tropics of Cancer the ecliptic’s Midheaven falls together with the sky’s Zenith point. Understanding the significance of the Midheaven — Zenith overlap allows us to consider a possible method of reconstructing the Nabta Playa stone circle.
The ancient Nubians were able to predict the summer and the winter solstice by preserving the angle of the ecliptic’s path at maximum tilt during the autumnal equinox’s midnight hour. More importantly they used the Nabta Playa stone circle to track meridian stars, which could have included the autumnal equinox’s prime meridian as exemplified through the star Bellatrix. Another example was given using the winter solstice’s prime meridian star Marbeb (Vela).
The Nabta Playa stone circle pays homage to the constellation of Orion through three signature stones. For us these stone placements serve as timestamps.
In 4461 BCE the Milky Way crosses the ecliptic, celestial equator and the autumnal equinox’s prime meridian at midnight.
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References
[1] Nabta Playa and the Ancient Astronomers of the Nubian Desert — https://www.ancient-origins.net/ancient-places-africa/nabta-playa-and-ancient-astronomers-nubian-desert-002954
[2] Nabta Playa stone circle — https://en.wikipedia.org/wiki/Nabta_Playa
[3] Elephant rock art — https://exhibitions.kelsey.lsa.umich.edu/graffiti-el-kurru/rock_art.php
