by Chas Parker

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The Royal Greenwich Observatory, which closed in October 1998, enjoyed a glorious history, spanning over 300 years. Initially located at Greenwich, it ended its days at Cambridge, but it was during its time at Herstmonceux in East Sussex, particularly in the sixties and seventies, that it was perhaps at its most vibrant.

The thing that set the Observatory apart, of course, was the people. With a staff of over 200 during its heyday, it was the unique mix of skills and personalities that made the place what it was and enabled it to enjoy a world-wide reputation for excellence.

But how did an establishment, known as the Royal Greenwich Observatory, come to be situated in 380 acres of Sussex countryside just outside a village with a decidedly French-sounding name?


When the Royal Observatory had been founded in 1675, Greenwich had been a village in open countryside, several miles outside London. With the growth of the capital, however, the area became urbanised and gradually deteriorated as an observational site.

Smoke from factories and houses, along with mercury vapour street lighting, meant that by the end of the second world war, the only option was for the Admiralty, which in those days was responsible for the running of the Observatory, to re-locate it.

After what are described as ‘extensive investigations’, Herstmonceux in Sussex, ten miles north of the resort of Eastbourne, was selected as its new home. Because of the importance of the establishment, and the fame of Greenwich, it was re-named the Royal Greenwich Observatory, Herstmonceux. To those who worked there and their colleagues in the astronomical community around the globe, it became known simply as ‘the RGO’.

In retrospect the site now seems an odd choice. In the past three decades virtually all new observatories have been sited on mountain tops, where the ‘seeing’ qualities are excellent and the number of clear nights per year is far greater than at lower levels. By contrast, Herstmonceux is nearly at sea level and lies adjacent to marshland, the mists from which sometimes made observing a problem. Even so, it probably enjoys more clear nights than any other site in the UK.


Whatever the site may have lacked from a climatic point of view, it more than made up for aesthetically. The 15th century brick castle, nestling between two gentle hills, provided the perfect environment for the astronomers and their colleagues.

Herstmonceux Castle was one of the first large brick buildings in the country. The name is derived from the Saxon word ‘herste’ meaning ‘a clearing in the woods’ and by which name both the manor and the family which lived there was known. A marriage between the de Herst and the de Monceux families in the twelfth century gave us the present name of Herstmonceux.

Originally constructed in 1441, the castle fell into decay and the interior was gutted in 1777. The ruins became a popular attraction until acquired by Colonel Lowther who began the reconstruction and renovation of the interior in 1911. The castle later passed into the hands of Sir Paul Latham who completed the restoration. Once purchased by the Admiralty, it became the home for the Observatory’s library, refectory, offices, the director’s residence and provided accommodation for astronomers and visitors.


Before we go any further, perhaps it is useful to look briefly at what the Observatory’s role was in those days. Its original purpose had been to map the heavens in order to improve navigation at sea. Over the years, this work on pure positional astronomy had led to investigations into the nature of objects such as stars and galaxies themselves, spawning the science of astrophysics.

Positional work still played an important part of course, with the annual publication of the Nautical, Air and Star Almanacs by the Nautical Almanc Office (NAO). These were published in collaboration with the United States Naval Observatory for use by astronomers, navigators and surveyors. Information included daily positions of the Sun, Moon, planets and natural satellites. The NAO was also responsible for supplying astronomical data for civil and legal purposes.

Other aspects of the Observatory’s work included investigating the earth’s magnetic field, determining the rotation of the earth and the measurement of time.

Greenwich Mean Time was, and still is, known the world over and it was the RGO’s responsibility to provide a national time service and to generate the familiar six ‘pips’ which were then broadcast by the BBC. It was because of this connection with time keeping that the Ministry of Defence’s Chronometer Department, responsible for the servicing and repair of Naval chronometers and RAF navigator’s watches, was also attached to the Observatory.

The many departments, in turn, were supported by mechanical, electrical and electronic workshops and laboratories, a drawing office and the usual administrative services that any large organisation requires. So the work of the RGO encompassed a number of different disciplines, each of which had to be accommodated at Herstmonceux.


The move from Greenwich was not achieved overnight, of course. In fact it took ten years, mainly due to the post-war shortages of manpower, building equipment and an initial lack of local housing for the staff. A group of Nissan huts provided temporary accommodation and the Astronomer Royal, Sir Harold Spencer Jones, moved into the Castle in 1948. No significant building work started until 1953 and it wasn’t until 1957 that the scientific staff left Greenwich and started work in offices within the castle.

During the war many of the departments had been evacuated from the capital, including the Time Department and the office of the Astronomer Royal, which were at Abinger, in Surrey, the Chronometer Department, which went to Bradford, and the Nautical Almanac Office, which was in Bath. Gradually the different departments and their staff transferred to Sussex and the establishment became whole again.

In addition to the facilities in the castle, a purpose-built block, known as the West Building was constructed to house the Nautical Almanac Office, the Time Department, the computer installation, and various other offices, workshops and laboratories. On the east side of the estate, on higher ground than the castle, the Equatorial Group of Telescopes was built.

Named after the ‘equatorial’ type of mounting that each of the telescopes utilised, this complex consisted of six domes, three of which were linked by a large building which housed photographic dark rooms, optical laboratories and an aluminising plant for the telescope’s mirrors. The other three domes were accessed by raised walkways and the whole complex was situated within an enclosure with flint-knapped walls and a large ornamental pond.


The reason this strange edifice had been constructed was the concern by the locals as to the impact on the environment the arrival of the Observatory was going to have. When the first small dome was erected to house the solar telescope, local residents expressed their dismay at this strange building. The outcry led to a severe delay in the design and construction of the Equatorial Group. The Fine Arts Commission was called in to give its views and the result was an attractive, but in some ways impractical, enclosure.

The architect had a difficult task: he was expected to construct six large domes for the telescopes, together with all necessary servicing facilities, and to make the resulting construction elegant and attractive. This he did very successfully but the night observers who subsequently worked in it would have preferred simpler designs more suited to their professional needs.

For example, one of the domes had its entrance only a few yards from the ornamental pond, and directly facing it. The story goes that one student, tired after a long night’s observing, stepped out of the dome and failed to turn left or right, with the inevitable result.

It was also at the Commission’s suggestion, that each of the domes was clad in copper so that, with the passage of time, they would gradually turn green and "blend in with the Sussex countryside".

Once the design had been settled, work was able to progress and the buildings were completed around 1956. The telescopes which had previously been at Greenwich, and which had been removed from their domes for safety during the war, were carefully installed in their new homes and by 1957 most of them were operational again.

The telescopes contained within the Equatorial Group were the Thompson 30-inch reflector, the Yapp 36-inch reflector, the Astrographic 13-inch refractor, the Thompson 26-inch refractor and the ‘Great Equatorial’ 28-inch refractor. A Schmidt camera was planned for the sixth dome but this was never installed.


To the north of the castle lay the Spencer Jones Group of Meridian instruments. These consisted of the Photographic Zenith Tube (PZT) which was used for time determination and for measuring latitude variation; the Danjon Astrolabe, also used for time and latitude determination; and the Cooke Reversible Transit Circle, used for determining star positions and planetary positions and motions.

Located between the castle and the West Building, the Solar Dome housed the Newbegin 6¼-inch refractor, the Photoheliograph and an underground Spectrohelioscope.

Extensive plantations around the estate helped reduce atmospheric turbulence while the woods and castle moat provided a habitat for a variety of wildlife. Also within the grounds were a cricket pitch, tennis court, swimming pool and a clubhouse, the latter built by the staff and including a licensed bar. The cricket pitch, in particular, saw good use during the time when Sir Richard Woolley, an ardent player, was the Astronomer Royal. At one match, the RGO took on, and beat, a World XI, consisting of internationally renown astronomers, most of whom had apparently only learned the rules of the game a few hours beforehand.

Woolley had taken over as Astronomer Royal from Spencer Jones in 1956. His intention was to build up the observatory, train new astronomers and thereby promote modern research into astronomy and astrophysics. He was the guiding light that helped the RGO establish itself at its new location and build even further on its world-wide reputation. One of the ways in which this was to be achieved was through the provision of a very large telescope on the site.


Long before the move to Herstmonceux, there had been talk of providing UK astronomers with a telescope large enough to allow them to compete on equal terms with their counterparts abroad, especially in the USA where a 200-inch instrument was in operation, and Russia which was building one of 237-inches.

It was eventually agreed that a 100-inch telescope be constructed, funded jointly by the Treasury and the Admiralty. The telescope would be for the use of all UK astronomers and, although located at Herstmonceux, would be administered by a Board of Management. It was RGO staff, however, who were to subsequently maintain and operate the telescope.

A 98-inch glass disk, originally intended for a telescope at Michigan University, was donated to form the prime mirror of the new instrument. After much discussion and delay concerning the design of the optical systems, mounting and guiding of the telescope, construction finally got underway. In 1967, Her Majesty the Queen performed the opening ceremony for the new Isaac Newton Telescope (INT) at Herstmonceux.

Over the years, the INT was used for a number of research projects. These included direct and electronographic photography of nebulae, galaxies and quasars, infra-red spectrometry and direct TV scanning of optical spectra.


Meanwhile, the other telescopes continued in regular use and it was not uncommon, on a warm summer’s night, to hear the strains of music across the air as one or more of the astronomers kept themselves entertained during a long observing session, playing tapes of anything from Bach to Led Zeppelin.

Other research work carried out by RGO staff included the determination of radial velocities, parallaxes and proper motions of stars, the study of globular clusters and the Magellanic Clouds, the measurement of the chemical composition of different stars and research into black holes. In 1971 an RGO team identified the X-ray source known as Cygnus X-1 with a particular star, which was thought to be part of binary system, the partner of which was most likely a black hole.

Astronomical research is not just carried out at night, of course. The shelves of the RGO library, which occupied a large portion of the castle, contained every significant book relating to astronomy that had been published in the past 300 years. The RGO’s archives also included the correspondence of all the previous Astronomers Royal. This treasure of astronomical lore attracted researchers and historians of astronomy who came from all over the world to search the records.


The RGO also played a significant role in the training of new, young astronomers. Woolley was instrumental in ensuring that astronomy was included on the syllabus at the nearby University of Sussex, at Brighton. From 1965 it was a recognised subject for MSc and D.Phil degrees and some RGO staff became visiting members of the faculty.

Other students benefited from the annual summer vacation courses run at Herstmonceux. Many of today’s astronomers cut their teeth in this way, spending a summer living in the Castle, observing on the telescopes at night, enjoying the a game of cricket at the weekends and retiring to the bar afterwards. To a young, aspiring astronomer, it must have seemed like heaven.

Another annual event was the Herstmonceux Conference. This was established by Woolley in 1957 and was held each spring on a different subject of topical interest. Over the years, leading astronomers from all over the world in a wide range of astronomical disciplines enjoyed the unique atmosphere and hospitality of these conferences. The RGO was enjoying its heyday at Herstmonceux.


By the mid-seventies, though, things had begun to change and the probable start of the decline of the RGO can be traced back to the opening of the INT in 1967.

Up to the time the decision to build a large telescope was taken, astronomers had to make do with whatever facilities were available in their own country. With the advent of cheap air travel in the 1960s, however, it became feasible for them to travel abroad and use telescopes which enjoyed better weather conditions than the UK could provide. The result was that, almost as soon as it opened, it was realised that the INT was in the wrong place.

The bigger and more powerful a telescope is, the better the site it needs to realise its potential. A large telescope will be used to look at the faintest, most distant objects and to glean the most information possible about them. It therefore requires the very best observing conditions that can be obtained. Such conditions are found at higher altitudes than Herstmonceux, usually on the top of mountains.

Smaller instruments, like the others at Herstmonceux and used for different types of observation, can cope with less than perfect conditions. The INT, during its time in Sussex, was used for only about a third of the time it could have been had the climate been kinder. It was little wonder then, that in the early seventies, a decision was taken to move it to an overseas site in the northern hemisphere, where it could be put to better use.

After testing various sites, including Hawaii, the Canary Island of La Palma was chosen and plans made to establish an international observatory there. In 1979 the INT was removed from its dome at Herstmonceux to be completely refurbished and fitted with a new mirror, before being shipped to the Canaries.


Other changes were also under way. The 1950s and ‘60s had been a period that saw great advances in science and technology, and these were to have a profound effect on the work of the Observatory.

The first computer was acquired in 1958 – by today’s standards a primitive device with a memory of one kilobyte and which could only be used to speed up calculations. Even so, it quickly made an impact and within a few years was replaced by a much more powerful machine. As computers became smaller and more powerful, they came to be used for other purposes, until it was difficult to find an instrument of any type, including the telescopes, that was not computer controlled.

In the 1950s and ‘60s, most junior staff were recruited from secondary schools with ‘A’ or ‘O’ level qualifications, and they learned astronomy through the performance of their duties. The operation and maintenance of the new technology, however, required operators with specialist training in many fields to carry out the research and instrument development. As a result, by the eighties an honours degree or a PhD were the minimum qualifications needed to join the scientific staff.

Perhaps the greatest effect that the advance of technology had was to make some of the traditional work of the RGO redundant. In the past, the Admiralty had needed accurate time, propagated by radio time signals, as an aid to navigation. During the mid-seventies, the Time Department, in collaboration with the US Naval Research Laboratory, took part in experiments in the distribution of time using earth satellites, which was to lead to the establishment of the Global Positioning System of navigation.

This, together with the ever-increasing accuracy of atomic clocks, meant that there was no longer a requirement for a national time service. Accurate time could be easily and readily obtained via satellite. The development of automatic transit instruments and dedicated satellites also meant that observations for positional astronomy no longer had to be made at Herstmonceux.

The Solar Department was closed down and the instruments replaced by the Satellite Laser Ranger (SLR). This specialised instrument measures the distance to specially designed satellites to within a few centimetres, by sending a pulse of laser light and measuring the time it takes to return. The laser pulse is reflected by mirrors on the satellite which direct it back in the direction from which it came. Other stations around the globe make similar observations and the results are used to study the rotation and gravity field of the Earth. Results from this meant that the Time Department’s Photographic Zenith Tube was no longer required.

Gradually, the need for the fundamental services which had once been the raison d’être of the RGO, was slowly eroded.


Once the INT ceased operating at Herstmonceux, all thoughts were focused on its new home. However, the work of establishing an overseas observatory, which was known initially as the Northern Hemisphere Observatory (NHO) and later as the Roque de los Muchachos Observatory, was a drain on the resources of the RGO. Science, and astronomy in particular, has never been over-funded in the country and setting up a project team of design engineers and optical experts meant that resources for other work diminished.

The result was that when maintenance or repair work was required on some of the telescopes of the Equatorial Group, there was neither the manpower nor the money to undertake it. The instruments, whilst still being used as best they could, began to be run down.

Policy decisions within the RGO were partially to blame, as was the direction in which astronomical research had gone. The forefront of research no longer concentrated on ‘nearby’ objects such as stars and neighbouring galaxies but lay instead in the furthest known objects, such as quasars and other distant galaxies. Those involved in stellar research saw their budgets cut first and the morale of some of the staff began to fall.

It had not always been like this. In the fifties and sixties, the majority of staff lived in the nearby village of Herstmonceux itself. Private cars were relatively few and so the facilities that the castle and clubhouse offered meant that it was only natural that staff and their friends spent much of their leisure time there. The RGO was truly a focal centre for village activities.

In the sixties, more people began to own their own cars and living close to your place of work was no longer a necessity. As some staff began to live slightly further afield, so the desire to drive back to work for leisure reasons declined. By the mid-seventies the clubhouse was still actively used, but nothing like to the extent that it had been. A decade later, with morale at an all time low, there was little desire among the staff to socialise.


By this time, the RGO had also seen a number of changes at the top. Woolley had retired in 1971 and was succeeded by Margaret Burbridge. The powers that be took the decision that, for the first time, the posts of director of the RGO and that of Astronomer Royal should be separated. No individual was to hold these posts at the same time again.

Burbridge’s stay was a short one. She and her husband, also a prominent astronomer, were vocal in their condemnation of the siting the INT. Their scientific conclusions were correct, but they won themselves few friends. Burbridge retired from the post in 1973 after a serious road accident.

She was succeeded by the, then, deputy director, Alan Hunter. Hunter was a popular figure appointed to oversee the Tercentenary celebrations of the Observatory in 1975. After his retirement, later that year, the post was taken by Professor Francis Graham Smith, a radio astronomer.

It was Smith who saw the RGO through the NHO project up until his own retirement in 1981. His successor, Professor Alec Boksenberg, would be the last of the directors of the RGO at Herstmonceux.

Boksenberg’s style was different to that of any of his predecessors. He was younger, and came from an instrumentation background (he was the inventor of the Image Photon Counting System (IPCS), a ground-breaking instrument which came to be universally used in astronomy).


The expertise of the RGO was now fully focused on La Palma, particularly the design and construction of the giant 4.2 metre William Herschel Telescope and all its associated instrumentation. Development of instrumentation was, in fact, one of the RGO’s greatest strengths. From the early days of image tubes to the Charge-Coupled Device (CCD) detectors of the eighties, the RGO research teams were at the forefront of development.

Now, with all effort abroad, and the RGO charged with operating the La Palma telescopes on behalf of the UK astronomical community, it didn’t take long for someone to question whether that role couldn’t best be carried out from a different location.

The arguments went along the lines of: "why do you need a 15th century castle and 380 acres of Sussex countryside to run an overseas observatory?" The answer, of course, was that you don’t, but many felt that if funding were made available to keep the other telescopes running, they could still be have been used for valuable research, for testing new instruments and for training students. The arguments were to fall on deaf ears.

It has never been a policy of any British government to fund any basic research that does not have some practical purpose. That is left to the universities. With the decline of fundamental work, such as time determination and positional astronomy, the very need for a national observatory was being questioned.

In 1965, responsibility for the RGO had passed from the Admiralty to the newly-formed Science Research Council (SRC) later to become the Science and Engineering Research Council (SERC). Report after report was instigated by the SERC, each one detailed to examine the workings of the observatories – not just the RGO but also the Royal Observatory, Edinburgh. Instead of being able to concentrate on their work, staff spent much of their time writing reports justifying what they were doing.

Many of the scientific arguments for the RGO to leave Herstmonceux were justified, but there was a feeling amongst some of the staff that a hidden agenda existed. Protests were dismissed as being ‘parochial’ and, eventually, it was announced that the Observatory was to re-locate to Cambridge, on a site adjacent to the University’s Institute of Astronomy. In 1990 the RGO moved for only the second time in its existence. Less than ten years later it was shut down completely.


From today’s perspective, life at the RGO during the early years at Herstmonceux must have been unbelievably idyllic. The staff were working in extremely pleasant surroundings, many pursuing research into a subject dear to their hearts, and everyone feeling that they belonged to something worthwhile, indeed that they were doing something worthwhile themselves. This was, after all, the Royal Greenwich Observatory. The setting of the castle and its grounds were far removed from an office in a city centre. This was the days of jobs for life. Conditions of employment were linked to the civil service and staff enjoyed good holiday allowances, a guaranteed job and a pension at the end of it. The pay may not have rivalled that available in outside industry, but that didn’t matter.

Idyllic as it sounds now, it wouldn’t have been any different from what people expected though. The sixties was a time of optimism across the country. If you worked at the RGO life was relaxed, there was cricket in the summer and the living was easy. The problems that afflicted the RGO during the seventies and eighties were the same problems that were affecting society: uncertainty about the future, concerns about funding, adapting to new technology and a culture change to a more commercial way of thinking.

The RGO may have only spent ten per cent of its long history at Herstmonceux, but it is not unreasonable to describe that time as a sort of ‘golden age’ when the best and most innovative work was done. Its passing from the site merely reflected the passing of an age and its like will never be seen again. The RGO at Herstmonceux was truly unique.

February 1999


The Royal Greenwich Observatory, W H McRea, HMSO 1975; Royal Greenwich Observatory, Herstmonceux Castle, eds P G Murdin and C A Parker, SERC 1987; Greenwich Observatory, ed C A Ronan, Times Books 1975; The History of Herstmonceux Castle, D A Calvert, RGO 1980; The History of The Royal Observatory and Royal Greenwich Observatory, Laurie Project Community Programme, consultant A J Perkins, 1987.

This article is dedicated to the memory of Dr Bill Martin, one of the many wonderful characters who made the Royal Greenwich Observatory the unique place it was, and who so sadly passed away on 15 January 1999.

Chas Parker worked at the RGO in a number of capacities from 1973-89, ultimately as press officer. He now works as a freelance writer and was involved in establishing a hands-on Science Centre which now occupies the old telescope buildings at Herstmonceux.

"Castle in the Sky"
is reprinted with permission
from Patrick Moore, ed., The  Yearbook of Astronomy 2000 (London: Macmillan Publishers, 2000).
CLICK HERE to go to the Yearbook of Astronomy website.
CLICK HERE to go to the Macmillan website.

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