The Observatory

The College’s Blackett Observatory is named after Sir Basil Blackett, one time President of the Old Marlburian (OM) Club; its telescope (the Barclay) is the largest in full time use in any school.

The observatory, or dome, is used today to support our GCSE Astronomy course. All Shell pupils visit the dome in House groups over the first two terms of their time at Marlborough and ‘Outreach’ encourages use of the dome by those outside the College community, including children from primary and prep schools, Scouts, Cadets, the WI etc. ‘Friends of the Marlborough Telescope’ is a group of local observing enthusiasts who have an annual diary of events to attend.

The Barclay Telescope 

The Barclay equatorial telescope housed in the observatory is a 10” aperture refractor constructed in 1860 by Thomas Cooke and Sons of York. When built, it was the fourth largest telescope in the UK; it was used professionally for 75 years, first in Essex and then at the Oxford Radcliffe Observatory.

History and Renovation

When the Oxford Radcliffe Observatory was being re-sited to South Africa, Sir Basil Blackett raised 800 guineas so that the Barclay Equatorial refractor that had formerly been housed at Oxford could be moved to its current location on the Marlborough College playing fields. It was opened there in 1935 by Harold Knox-Shaw, the last Oxford based Radcliffe Observer.

In 1997, the College funded a five year restoration plan to completely renovate, re-motorise and computerise the main telescope. The Observatory and telescope were re-opened in October 2002 by Oxford University’s Savillian Professor, Joseph Silk, FRS.