Dr Euan MacKie's letter (December 28) gains added poignancy from the near-simultaneous announcement of the death of Professor Archie Roy.

I first learned of the astronomy of ancient Britain when I studied under Dr Roy (as he then was) in 1963-65, and he proposed me for manager of the Glasgow Parks Astronomy Project, which built the first astronomically aligned stone circle for more than 3000 years, in Sighthill Park in 1978-79. The original brief was to build a copy of an ancient site in modern materials, but once I had shown the need to design a new monument according to ancient principles, I urged that we build it in stone and dedicate it to Professor Alexander Thom, Dr Archie Thom, Dr MacKie and Dr Roy, all experts in ancient astronomy and all connected with Glasgow University and the city.

With Prof Roy's death, Dr MacKie is the only remaining dedicatee, and this comes at a time when the future of the stone circle is under threat. At a meeting with Glasgow City Council's Development and Regeneration Services (DRS) in November I was told the circle had to be demolished at an early date, to check the ground for chemical contamination, in order to show Glasgow is serious about bidding for the Youth Olympics in 2018. However those checks had to be made in 1978 before planning approval for the circle's foundations was granted, and the trenches dug for the foundations proved the ground was clean. I was shown plans for a "green pedestrian street" to run from Springburn to the M8, but putting a bend in it would bypass the stone circle and make it an attraction instead of an obstacle.

At the meeting with DRS I was challenged to give numbers of people who visit and use the circle. I couldn't do so then, but the hundreds of people who have now signed the petition – www.sighthillstonecircle.net, Save Our Stones – with added comments, make clear that it means a great deal, to many people. Despite what I was told in November, there have been five statements from the council saying no decision on the circle's future has been taken, and this would be a good time for a promise to let the circle stand.

Duncan Lunan,

Friends of Sighthill Stone Circle,

26 Dallas Place,

Troon,

South Ayrshire.

Eoghann MacColl (Letters, December 29) correctly explains that the Sighthill standing stones should be developed rather than razed to the ground as a concession to the need for a car park or whatever.

The Sighthill stones should be a trigger for Scots and others to wonder at the significance of stone circles in Scotland such as the circle at Brodgar in Orkney.

Five thousand years ago, a thousand years before Stonehenge was erected, the people of Lewis built a stone circle at Callanish on the west coast. Research by Prof Thom, Gerald Ponting and others gives a strong indication that those people could predict the movements of the moon in its orbit using the peaks of the Clisham in Harris as a silhouette – a kind of foresight for the alignment of the cross-shaped avenues that focused on the inner circle.

Such knowledge provided an insight into such crucial information as why the tides around the coast ebbed and flowed as they did. This wisdom was vital to the lives of a people dependent on travelling by sea. They settled in Callanish, and other circles were erected in the vicinity. They may well have been fertility rings, and further investigation is required. The people would be aware of the importance of the sun and the seasons as they farmed the land where they had come to stay.

They would be intrigued by the patterns of the stars. There may well have been a religious component to the efforts of the people to understand the cosmos.

What should be clear is that the achievements of our ancestors should inspire us to look to the future, with a greater understanding of our past.

Alasdair H Macinnes,

96 Granton Road, Edinburgh.