Astronomers and archeologists are examining whether certain megalithic tombs found in Europe could have been used to enhance our ancestors’ vision of the night sky.

The UK-based team suggests that the long, narrow entrance passages might be akin to a pinhole, creating some sort of lensless telescope. The scientists plan to test this idea with the 6,000-year-old Seven-Stone Antas passage grave in central Portugal.

“The orientations of the tombs may be in alignment with Aldebaran, the brightest star in the constellation of Taurus,” said team member Dr Fabio Silva of the University of Wales Trinity Saint David in a statement. “To accurately time the first appearance of this star in the season, it is vital to be able to detect stars during twilight.”

If the narrow passages did indeed allow our ancestors to spot Aldebaran, it might have been used for seasonal timing or rituals. 

Kieran Simcox, a student at Nottingham Trent University who led the project, commented: "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."

This work was presented at the National Astronomy Meeting in Nottingham this week and it highlights how astronomy has been closely interwined with human culture for millenia. 

^{Photographs of the megalithic cluster of Carregal do Sal: a) Dolmen da Orca, a typical dolmenic structure in western Iberia; b) view of the passage and entrance while standing within the dolmen's chamber: the "window of visibility"; c) Orca de Santo Tisco, a dolmen with a much smaller passage or corridor. F. Silva}