First Astronomical Observing Tool: 6,000-Year-Old Tombs Were Used As Telescopes By Ancient Stargazers – Ancient stargazers used 6,000-year-old tombs to set calendar dates and watch the heavens thousands of years before Galileo Galilei.

Astronomers are exploring what might be described as the first astronomical observing tool potentially used by prehistoric humans 6,000 years ago.

The study conducted by astronomers at Nottingham University reveals that Megalithic tombs could have been designed as ingenious tools to observe the faintest stars – effectively telescopes without lenses.

Ancient tombs used as telescope
view of several ancient passage graves.a) Dolmen da Orca in Western Iberia, b) the window of visibility from within the the chamber, c) Orca de Santo Tisco in Portugal. (Credit: F. Silva)

Ling narrow entrance passages to ancient stone, or ‘megalithic’, tombs, aligned to certain stars may have enhanced what early human cultures could see in the night sky, an effect that could have been interpreted as the ancestors granting special power to the initiated.

The focus of 13 of the tombs in Carregal do Sal, Portugal appears to be Aldebaran, the brightest star in the constellation of Taurus.


The researchers suggest that this could be for ceremonial purposes.

Ancient History Facts: First Astronomical Observing Tool: 6,000-Year-Old Tombs Were Used As Telescopes By Ancient Stargazers

“The orientations of the tombs may be in alignment with Aldebaran, the brightest star in the constellation of Taurus. To accurately time the first appearance of this star in the season, it is vital to be able to detect stars during twilight. Rock art and paintings, some of which are present inside similar passage graves, could and have been interpreted as red stars, much like Aldebaran itself,” Fabio Silva, of the University of Wales Trinity Saint David said.

Aldebaran is the Bull’s fiery eye.

When the tombs were built, around 4,300 – 3,700 BCE, Aldebaran would have risen between 18 and 27 April and appear from within all of the entrance passages of the tombs.

See also:

Namoratunga: ‘People Of Stone’ And Ancient Astronomical Observatory

Mystery Of The Gotland Grooves – Ancient Astronomical Observatory?

Stones Of Rajajil – Sophisticated Road Markers Or An Ancient Astronomical Observatory?

The first sighting in the year of a star after its long absence from the night sky might have been used as a seasonal marker, and could indicate for example the start of a migration to summer grazing grounds. The timing of this could have been seen as secret knowledge or foresight, only obtained after a night spent in contact with the ancestors in the depths of a passage grave, since the star may not have been observable from outside. However, the team suggests it could actually have been the result of the ability of the human eye to spot stars in such twilight conditions, given the small entrance passages of the tombs.

Ancient tombs used as telescope
The graves, which are also found in Spain, are ancient tombs made of several huge slabs of granite stone, which point in the direction of the arc of sunrise. Pictured is tomb in Orca de Santo Tisco, Portugal Image credit: F.Silva

“It is quite a surprise that no one has thoroughly investigated how for example the colour of the night sky impacts on what can be seen with the naked eye,” Kieran Simcox from Nottingham Trent University and a leader of the project said.