Digging an ’‘Imperial Philosophical Machine’: Iron Age and Telescope Archaeology at the University of Cambridge Observatory

An archaeological dig in Cambridge has uncovered surprising ancient remains and the foundations of the world’s largest telescope of the late Victorian era.

Archaeologists from the University of Cambridge Archaeological Unit, recently working at the site of the new Kavli Institute for Cosmology in the grounds of the University’s Observatory in west Cambridge, have unearthed an extraordinary series of deposits.

The Observatory hill-top has long been known as both a location of early settlement and, in Medieval times, as Gritrow , a hamlet specialising in gravel quarrying. Accordingly, the site was peppered with oblong pits characteristic of small-scale quarrying, themselves dated to the 16 to 18th centuries.

However, within their fills were also found significant quantities of Iron Age and Early Roman pottery, indicating that the early settlement had been destroyed and redeposited by the quarrying.

Moreover, appearing like some sort of giant bull’s-eye, cut down through the quarries was the 13m diameter, brick-and-concrete ring foundation (with an enormous plinth in its centre) of the Newall Telescope.

With a 25” lens, this was for a time the largest telescope in the world. Completed in 1871 for wealthy businessman Robert Stirling Newall, its tube is cigar-shaped, nine meters long and weighs 9 tons.

It was donated to the University in 1889 and housed in a purpose-built dome on the site. It stood there until 1955 when its mechanism was moved to the National Observatory of Athens, where it survives.

Christopher Evans, Director of the Archaeological Unit, reports: “We know what the above-ground portions of early telescopes looked like from standing examples, photographs and plans, but this is one of the very few excavations of their below-ground components. Their foundations really were truly massive, absolute stability being of paramount importance for large telescopes.

“In fact, with its perfect circle looking in the ground rather like a prehistoric monument, in its time the telescope was referred to as an ‘imperial philosophical machine’: a tool by which western science could measure or control universal space/time. Interestingly enough, this is also exactly how many archaeologists interpret Stonehenge and other early monuments!”

The dig was directed by Richard Newman. The Cambridge Archaeological Unit was founded in 1989 by Christopher Evans and Dr Ian Hodder and operates out of the Department of Archaeology, University of Cambridge.

On all types of projects the CAU offers a full range of archaeological services supported by the academic and scientific expertise of the University.

Led by Professor George Efstathiou, the Kavli Institute for Cosmology will be supported by a multimillion dollar endowment from the Kavli Foundation which is dedicated to advancing scientific knowledge “for the benefit of humanity”.

The researchers of the new institute will seek to make major scientific advances in our knowledge and understanding of the universe, bringing together scientists from Cambridge’s Institute of Astronomy, the Cavendish Laboratory (the Department of Physics) and the Department of Applied Mathematics and Theoretical Physics.

The start of construction of a £4 million building for the Kavli Institute, designed by Annand & Mustoe architects is imminent.

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.