In the vaults of the Royal Society Library, Virginia Mills digs up some past research into the connection between celestial phenomena and ancient monuments.

Photograph taken by Norman Lockyer at Stonehenge in 1901 (detail)

I was excited to read a recent report on how the major lunar standstill in January 2025 will be the subject of a new research project at Stonehenge. This led me down into the vaults of the Royal Society to excavate past investigations into the connection between celestial phenomena and ancient monuments.

Many past Fellows of the Society have studied the most famous British examples of these sites, including Stonehenge and the standing stones at Avebury. The first systematic surveys of the two were by John Aubrey FRS (1626-1697), who had been captivated by Avebury since coming across it aged 23. In 1663, Aubrey investigated both locations at the behest of King Charles II (after an introduction facilitated by the first President of the Royal Society, Viscount Brouncker), and continued to favour Avebury, saying that ‘this old monument does as much exceed in greatness the so renowned Stoneheng, as a Cathedral doeth a parish Church’!

John Aubrey’s plan of the megalithic site at AveburyAubrey’s plan of the megalithic site at Avebury (MS/131/67)

Aubrey was one of many antiquaries amongst the Fellowship of the early Royal Society. In the seventeenth century there were already, as now, several theories about the origins and significance of Stonehenge amongst these learned amateurs. By his own assertion, however, Aubrey was the first to suggest it was more archaic than a Roman or Danish settlement, based on his close study of the site and comparison with other ancient monuments:

‘There have been several books writt by learned men concerning Stoneheng, much differing from one another, some affirming one thing, some another. Now I come in the rear of all by comparative arguments to give a clear evidence that these monuments were Pagan Temples … This enquiry, I must confess, is a gropeing in the dark: but although I have not brought it into a cleer light yet I can affirm that I have brought it from an utter darkness, to a thin mist... These Antiquities are so exceeding old that no bookes doe reach them, so that there is no way to retrive them but by comparative antiquitie, which I have writt upon the spott from the monuments themselves.’

Aubrey’s approach of personal observation, or (as he said) ‘letting the stones speak for themselves’, reflected the new science as championed by the Royal Society, with its motto nullius in verba. The teachings of those who would become the Society’s founding members had already influenced Aubrey as a student at Trinity College Oxford and Middle Temple. While he has also been described as too credulous, particularly in connection with his folklore-gathering and speculation about druidic practices, his work as a forerunner of formal archaeology is undisputedly pioneering and revolutionary.

His descriptions of Stonehenge and Avebury, completed in 1665, developed into the 1693 manuscript Monumenta Britannica. Though not published in Aubrey’s lifetime, this is considered a foundational work of archaeology and the study of pre-history, and significant in calling for such monuments to be studied and protected. The plans Aubrey made of Avebury are the oldest of the site and an invaluable record of a national monument that has undergone further transformation and losses since. The plan in the Royal Society archive, shown above, is particularly detailed.

John Aubrey's telescopic observation of a nebula, 1668A telescopic observation of a ‘nubecula’ (nebula) by John Aubrey (CLP/8i/24)

While Aubrey dabbled in astronomy as well as being an antiquary, he never made any connection between British megalithic monuments and the stars. Instead, in his 1720 survey of Stonehenge, the antiquary William Stukeley FRS (1687-1765) identified the orientation of the layout with the midsummer sunrise. So, it is Stukeley we can thank for the revival of the solstice gatherings that happen to this day.

In addition to his own infamous theories about the druids, Stukeley thought the near-alignment of the heel stone in relation to the solstice in the eighteenth century would enable him to date Stonehenge. Assuming (erroneously and anachronistically) that the site had been laid out using a magnetic compass, he posited that the date the solstice sunrise had perfectly aligned with the heel stone would be the date of construction. He argued that this could be determined by calculating the time it would take for the magnetic variation causing the perceived misalignment to have occurred – a significant early attempt to date an ancient monument using scientific methods.

However, given that modern scholarship suggests that alignments at Stonehenge can only be treated as approximate, this flawed approach was never going to lead to a meaningful conclusion on the construction period. With the assistance of astronomer Edmond Halley FRS, the earliest date Stukeley arrived at was 460BC; Stonehenge is now thought to have been constructed between 3000BC and 1600BC.

Medal of William Stukeley with an image of Stonehenge (© The Trustees of the British Museum)Commemorative medal of William Stukeley with an image of Stonehenge. Image © The Trustees of the British Museum (reproduced under CC BY-NC-SA 4.0). See also Royal Society M/217

Another attempt was made to date Stonehenge astronomically in 1901, when theories as to its age still varied by thousands of years. This was the work of Sir Norman Lockyer FRS (1836-1920), considered to be the founder of modern archeoastronomy. Lockyer published five papers on stone circles in the Proceedings of the Royal Society, the first concerning the date of Stonehenge.

This was a continuation of work he had undertaken on Greek and Egyptian monuments and, like Stukeley’s attempt nearly 200 years earlier, was based on the orientation of the site. Lockyer compared the earthen bank avenue extending from Stonehenge to avenues of sphinxes attached to Egyptian solar temples. He believed Stonehenge to have been a roofed solar temple, with the avenue serving to channel the midsummer sun into what would otherwise have been a dark interior, adding drama to the main religious celebration at the solstice sunrise.

He took meticulous new measurements but still relied on interpretation of the remains, obfuscated as this is by the long history of construction, decay and restoration, with many of the stones possibly no longer in their original positions. His work is now considered to be based on poor assumptions about the archaeology. While he also suggested that Stonehenge may have had other astrological functions, Lockyer focused solely on solar rather than lunar astronomy.

Photograph taken by Norman Lockyer at Stonehenge in 1901Photograph taken by Lockyer at Stonehenge in 1901

The new studies during the upcoming lunar standstill will include analysis of the Aubrey holes. Named for John Aubrey – though they may not be those that he originally observed – these are 56 pits in the earthen bank where cremated remains and offerings have been found, and which correspond with the southern extremity of moonrise as it occurs during the standstill. Stonehenge still captivates because of its mystery as well as its antiquity and majesty, but maybe the next phase of scientific study will help to demystify its connection with astronomy a little further.


  • Virginia Mills

    Virginia Mills

    Virginia is the Royal Society’s early collections archivist, responsible for looking after the pre-1900 material in the archive and the records of the past Fellowship. She has previously worked in other scientific archives at the Royal Botanic Gardens, Kew and the Natural History Museum, London.