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The Observatory Science Centre
East Sussex
BN27 1RN
Tel: 01323 832731
Fax: 01323 832741

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50th Anniversary of the INT

Friday 1st December 2017

7.30pm - midnight

Join us to celebrate this momentous anniversary with memories and anecdotes from some of the people who worked with the Isaac Newton Telescope (INT).

On the 1st December 2017 it will be 50 years to the day when the Queen inaugurated the INT on the 1st December 1967. 

The Centre will open at 7.30pm, and during the evening there will be the opportunity to join us for an overview of the history and work of the INT at Herstmonceux by Professor Paul Murdin, followed by a small number of short talks from former RGO astronomers, including:
Dr Bob Fosbury of the ESO Astronomy Faculty, Professor Donald Lynden-Bell of the Institute of Astronomy, Cambridge University, Chas Parker, former RGO PR Manager and Keith Tritton, former head of the Isaac Newton Group on La Palma. We will also be joined by the director of the Isaac Newton Group on La Palma, Dr Marc Balcells who will be talking about the current and future use of the INT. With everything crossed we will also be having a live link with La Palma and live observations.

The evening will end, weather permitting, with viewing through the historic telescopes of the Equatorial Group.


How to Book

Tickets cost £10 and are available in advance by telephoning the Centre on 01323 832731. Alternatively you can book online by following this link Eventbrite. Please note that online booking incurs a booking fee


For the past fifty years, a large metallic dome has been an iconic feature of the Sussex landscape, standing like a sentinel on the edge of the Pevensey Levels. Now mostly concealed by trees, it was once far more visible and still continues to be a navigational aid for shipping in the English Channel. However, for many people, both local and visitors to the area, it remains an enigma. What was its purpose and what of its fate?

The dome housed the Isaac Newton telescope which at the time of its inauguration by Her Majesty The Queen in 1967 was the largest reflecting telescope in Western Europe and the fifth largest in the world. It was installed in the grounds of the Herstmonceux Castle estate, then home to The Royal Greenwich Observatory which had relocated to the clearer skies of Sussex in the 1940s and 50s.

The Isaac Newton Telescope (INT) cost approximately £1 million including the dome and featured a large 98-inch (2.5 metre) primary mirror which enabled it to collect light from extremely faint and distant objects in the night sky. One of the INT’s notable achievements came in the early 1970s when astronomers using the telescope helped to confirm the existence of the first black hole, a region of space where the gravitational force is so powerful that nothing can escape, not even light.

Although important research continued to be carried out by both Herstmonceux and visiting astronomers, the INT saw a mere twelve years of service in its rural Sussex location. Restricted viewing due to the vagaries of the British weather coupled with light pollution from the expansion of nearby towns such as Eastbourne brought about the decision to relocate the telescope to a new home on La Palma in the Canary Islands. Its final view of the night sky above Sussex was in March 1979.

With a new mirror and dome, the INT was back in regular service by 1984 and is still in use today, perched high above the clouds on La Palma’s Roque de los Muchachos. The original mirror is now on display at The Observatory Science Centre, Herstmonceux, within sight of that iconic dome.