Its purpose was a practical one: to reduce shipwrecks. At that time mariners had no accurate way of working out their position when out of sight of land. They could find their latitude (north-south position) by observing the sun or stars, but not their longitude (east-west position). As a result many sailors' lives were lost when their ships struck rocks unexpectedly. By the 1770s the problem of longitude had been solved. One answer was for a ship's captain to carry a reliable clock to keep ‘Greenwich Time' throughout the voyage. Alternatively he could use the Moon as a clock by measuring its position in the sky, relative to nearby stars, and referring to a detailed set of tables prepared annually at Greenwich. Armed with either of these timekeepers, or preferably both, mariners could make their own astronomical observations on board ship, and use them to work out their position anywhere on Earth. Solving the problem of longitude didn't mean the Observatory had nothing to do. The essential work of measuring time and compiling tables went on from year to year, and the Greenwich astronomers developed new interests too. In particular they began to do research,studying the stars and other objects in the sky, to find out what they are and how they work. The Royal Greenwich Observatory at Herstmonceux
By the early twentieth century, London had expanded so much that Greenwich was enveloped. The city's smoky air and bright lights meant that astronomers could no longer study faint objects in the night sky. The remedy was to move the whole Observatory to the clearer, darker skies of Sussex. The transfer began in 1947, and by 1958 the Royal Greenwich Observatory was fully up and running at Herstmonceux. At its peak, over 200 people worked at The Observatory in Herstmonceux and lived in the local community. The people who actually operated the telescopes at Herstmonceux were called ‘night observers'. They were on duty every night when the sky was clear and the Moon not too bright. On the Thompson 26-inch telescope, for example, the night observer's job was to line up the telescope on a succession of specified points in the sky, workingfrom a prearranged list of ‘shots', and to load in a photographic plate for each shot and expose it for a time that usually ranged from five minutes up to an hour or more. It was precision work which required much care and skill. Cold was a great enemy, since the domes had to be unheated to prevent currents of warm air blurring the photographs
The Equatorial Group at Herstmonceux
The building was constructed in the 1950's, and was built to house three reflecting and three refracting telescopes in the six green domes. It is known as the ‘Equatorial Group' after the way the telescopes are mounted. The architect was Brian O'Rorke and the work was completed in 1958. With its unique arrangement of domes around a central bastion the Equatorial Group was one of the most important government commissioned building projects of its period. The domes were clad in copper sheet and coated with a chemical that has helped them to weather to today's distinctive green - one of the features that was intended to make the buildings blend into the Sussex countryside. Modern observatories now have domes painted white or silver to reflect away any daytime heat. The base of the domes were faced with wood-burnt West Sussex brick. The balconies and window surrounds finished in Portland stone; the terrace paved in Yorkstone with Portland stone steps and edgings. The external walls were clad in knapped flint - a traditional Sussex finish, which was a further attempt by the architect to help the buildings ‘blend in'. Flint knapping is an ancient skill, also used to make stone tools and weapons, in which lumps of flint are shaped by striking them with preciselyaimed blows; in this case to form cubes with glassy blue sides. In the 1950's it proved difficult to find a flint knapper with the appropriate skills, but eventually a 90 year old gentleman from Lewes, East Sussex, was coaxed out of retirement. The buildings were finished to the highest standards and at considerable cost. However, astronomers found the layout inconvenient and even hazardous. Look around the site - at the various levels and walkways, and imagine this in the dark with few of the current railings in place. There are tales of the occasional stumble into the lily pond. The Observatory Science Centre
In 1990 The Royal Greenwich Observatory closed its doors at Herstmonceux and moved to Cambridge, leaving the historic telescopes behind. Five years later the Equatorial Group came back to life as The Observatory Science Centre, under the aegis of Science Projects. An extensive programme of repair and upgrading of the buildings and telescopes was completed in 2004 with the aid of a substantial grant from the National Heritage Lottery Fund. It is now a Grade II* listed monument. Along side the historic telescopes there are over 100 interactive hands-on exhibits and exhibitions.
