By Duncan Lunan
For at least two thousand years, and ending more than three thousand years ago, the British Isles supported one of the most advanced ‘colleges’ of astronomers in the ancient world. Until recently many archaeologists would have rejected that statement, but recent discoveries, particularly at Stonehenge, Durrington Walls and on the Ness of Brodgar in Orkney, have shown that there was indeed a neolithic culture, spanning not just Britain but Europe, which was capable of supporting such a ‘college’, and forces a new look at what it may have accomplished.
Those neolitihic people built stone monuments in North Africa, France and Spain, in Scandinavia and along the Mediterranean. Astronomical alignments were built into their tombs in Ireland, but it’s in Brittany, on the English and Scottish mainland, and in the western and northern isles, that their standing stones and circles have the characteristics of observatories. Almost certainly their interest in the movements of the Sun and Moon was prompted by navigation and by agriculture, and it is hard to imagine that key events like the solstices would not have been marked by religious rituals; but since no literature has come down to us, and there was no explicit carving on the stones, only the pure astronomy underlying the layout of the sites is still accessible.
The late Professor Alexander Thom, with his son Dr. Archie Thom, put decades of work into unravelling the geometries of the ancient sites. Much of that research was published in the 1960s, even before Prof. Gerald Hawkins brought the subject into prominence with his book Stonehenge Decoded. In the controversy which followed, many astronomers, including the late Prof. Archie Roy of Glasgow University, came to support the Thoms’ contention that the neolithic Britons were indeed astronomers. Since they did not build in brick, and did not practise metalworking until late in their history, the megalith builders had to reduce positional astronomy to precise observation of horizon events, and these were marked with stones. Thom published a histogram, showing the alignments of the ancient sites in relation to the movements of the Sun, Moon and bright stars; it was obvious that the relationships were far from coincidental, and later revision of radiocarbon dates only improved the correlations.
Archaeologists, however, were critical. Thom postulated a nationwide astronomical programme, working accurately with a fixed standard of length, moving northward to spread the events further along the horizon and observe the Moon’s motion with still greater precision – perhaps realising that in effect they were discovering the circumference of the spherical Earth. Many experts found it impossible to believe that such an advanced society could have existed in prehistoric Britain. One who supported Prof. Thom was Dr. Euan MacKie, whose excavations of megalithic sites such as Kintraw supported the astronomical interpretation. Circumstantial evidence for an advanced society was beginning to show even then; for instance, blanks for neolithic hand-axes were distributed throughout the country from a very few quarries.
In 1978 Glasgow District Council, as it then was, asked me to build a ‘mini-Stonehenge’ in one of the city’s parks, a a ‘special project’ in the Jobs Creation Scheme. The request was originally to copy one of the ancient sites, but that wouldn’t work: each megalith’s alignments fit its own date, latitude and skyline. For the monument to be functional and educational, as the brief required, I would have to find a suitable site and design the structure in accordance with the ancient principles. Professor Thom was previously the first Reader in Aeronautics at Glasgow University, and Dr. Thom was Acting Professor of Aerodynamics and Fluid Mechanics there at the time, while Euan MacKie was Assistant Keeper at the University’s Hunterian Museum and Archie Roy had recently become a Professor in the Astronomy Department after many years as Senior Lecturer. By building an astronomical megalith dedicated to them, the first apparently for 3000 years, the city would be paying tribute to its most prominent researchers in the field.
The chosen site was the viewpoint at the top of the new Sighthill Park, due north of George Square and overlooking the M8 motorway.
The stones came from Beltmoss Quarry in Kilsyth, and after the largest ones were positioned to mark the lunar alignments (on the advice of Prof. Thom), the solar and star stones plus the central stone were added by Royal Navy helicopter.
Work was then stopped by order of the government of the day, and after (incorrect) landscaping into the park in 1982, the circle remained untouched and unmarked until 2012, when the Planning Department announced that it and the park would be removed to make way for new housing.
Meanwhile, a campaign to renovate and complete the circle had been running under the Friends of Sighthill Stone Circle, and an online petition to save it attracted over 6500 signatures. It turned out that despite the lack of publicity for the circle, many people had been using it for their own private reasons, including private ceremonies by the Druid and Pagan communities, and even more private scatterings of people’s ashes by their loved ones. As a result of the campaign, Glasgow City Council announced that both the stones and the topsoil would be removed with care, to be replaced at a new site, whose location was agreed in 2016, before the stones were successfully removed intact in April that year by VSE, the contractors for the first phase of the redevelopment.
The time capsule was successfully recovered from the foundation of the central stone and will be replaced at the new site, when it’s opened to the public in summer 2020. By June 2017 the Phase 2 contractors, Morgan Sindall, had prepared a platform for the stones at the new site on the extreme eastern end of the former park, overlooking Pinkston Road.
Due to bad weather and other problems, I couldn’t start survey work at the platform until April 2018, and I didn’t get actual observations until midsummer sunset and a subsequent moonrise that June. With those as a starting point, however, I was able to reconcile all the observations which had been made over 40 years at the previous site, then adapt them to the lower viewpoint and different skyline at the new location. The first incarnation of the circle was created in a ‘Time Team’ style rush, and a great deal about the operation of the ancient sites has been learned from what I didn’t get quite right in 1979, but this time I’ve been able to make the alignments a great deal more accurate. The new ‘Interactive Sky Chart’ on the heavens-above.com website has been particularly helpful, especially when compared to the laborious spherical trigonometry I had to do in 1979 using pen, paper and logarithmic tables.
The new circle was completed by March 20th 2019, just in time for the spring equinox and the 40th anniversary of the helicopter operation.
Again there was a break in the weather just after the summer solstice, and a new set of observations show that the event is indeed in line with the marker stone. They’ve also confirmed what I found in re-evaluating the observations at the previous site: atmospheric refraction is much less of a factor than I had to assume in 1979, for all the horizon events except midwinter sunset, equinox sunset and midsummer sunset.
For all of those three, refraction is near the theoretical maximum value, and apparently independent of air temperature.
It’s being caused by something in the air at the end of sunny days, and the best guess is smog, caused by the action of sunlight on pollutants such as car exhausts. As well as the educational value of the recreated circle, its importance to Glaswegians and its attraction for visitors, the recreated circle may have important things to tell us over the next few years.
Currently the circle is off-limits to the public because it’s still part of a construction site, but it’s hoped that it will be opened to the public in time for the 2020 summer solstice. At present the best view of it is from the road bridge over the M8 motorway, where Baird Street runs on towards Pinkston Road and Springburn.
The story of Sighthill stone circle to mid-2012 is told in detail in Duncan’s book THE STONES AND THE STARS (Springer 2012), which is available from bookshops, or online from the publishers, or from Amazon and other outlets. More recent developments are on Duncan’s website, www.duncanlunan.com.