The Royal Observatory at the Cape of Good Hope (1959–1971)

In 1959, the Royal Observatory at the Cape of Good Hope became a branch of the Royal Greenwich Observatory, Herstmonceux. This relationship ceased at the end of 1971, when it was merged with The Republic Observatory, Johannesburg to form the South African Astronomical Observatory (SAAO).

The Main Building in 1967. Completed in 1828, the architect was John Rennie. Photo courtesy of Robin Catchpole


The founding of the Cape Observatory

The Royal Observatory at the Cape of Good Hope was established in Cape Town, South Africa in 1820 following a proposal by the Commissioners of the Board of Longitude.  It was the first permanent observatory in the southern hemisphere. Its main task was to extend the work of Greenwich into the southern hemisphere and to cooperate in the determination of fundamental astronomical data. The Admiralty, which had taken on new responsibilities for funding the Royal Observatory, Greenwich in 1818, was also responsible for funding the Observatory at the Cape. The Cape Observatory originally had its own Astronomer Royal but by 1855, this title had changed to Her Majesty’s Astronomer at the Cape. Of the nine holders of this post, three were former Chief Assistants at Greenwich. These were Edward Stone (1870–1879), Harold Spencer Jones (1923–1933) who returned to England as Astronomer Royal, and John Jackson (1933–1950). The last post holder was Richard Stoy. He served from 1950 until his resignation in 1968. Although the Cape Observatory was run independently of the Greenwich Observatory until 1959, there was normally, a great deal of cooperation between them. 


Location map


Links with the Radcliffe Observatory

In 1934, the trustees of the Radcliffe Observatory which had been founded in Oxford in 1773, decided to sell up and begin the process of erecting a new observatory some 800 miles to the north east of Cape Town in Pretoria. A 74 inch (1.8m) reflector was ordered from Grubb Parsons in 1935. Following delays caused by World War Two, the telescope was eventually installed in 1948. It was the largest telescope in the southern hemisphere and one of the largest in the world. It was also the Observatory’s only telescope.

Discussions about a possible cooperation with the Cape Observatory began prior to the telescope coming into service as the new observatory was underfunded and could not afford to employ either a mechanic or a secretary. These were taken up by the Astronomer Royal Spencer Jones when he visited the Cape in 1949. A three year agreement was made to lease a third of the time on the telescope to the Cape Observatory with effect from 1 April 1951. In 1954, the agreement was extended for a further five years. The initial cost to the Admiralty was £2,500 pa, increasing (according to Lovell) to £3,500 in 1957. In 1958, Richard Woolley (Spencer Jones’ successor as Astronomer Royal) secured a separate British Government grant for the Observatory of £30,000 over 5 years from the Department of Scientific and Industrial Research (DSIR). This was for a programme, the main purpose of which was a comparison of the Magellanic Clouds and the Galaxy and more particularly an extensive study of the Cephids and clusters in two areas of the Large Magellanic Cloud. Woolley visited the Radcliffe in December 1958 and together with Olin Eggen (one of his two Chief Assistants who had been on a six month secondment to South Africa since August), kick started the programme of observations in conjunction with a parallel series that were to be undertaken by staff at the Cape. Travel grants were also available though the DSIR, which allowed temporary visits from RGO staff and the University Observatories in the UK.


The Merger of the Cape and Greenwich Observatories

Soon after his appointment as Astronomer Royal, Woolley appeared before the Parliamentary Select Committee on Estimates (1956–57 Session, paper 199), where amongst other things, he was asked by Proctor if there would be any value in merging the Cape and the Greenwich Observatories? He replied (para. 299) that it was ‘a subject that might repay study’. The degree of cooperation between Greenwich and the Cape increased – initially with a programme of secondments that began when Patrick Wayman was sent to the Cape in April 1957 to help solve a staffing crisis. That same month, the Hydrographer to the Navy (to whom both Woolley and Stoy reported) touched on the matter of closer cooperation in a letter to Woolley.

Woolley wrote to Stoy about the matter on 3 June 1957. Stoy was keen on Woolley’s proposal to regard the RGO and the Cape as no more distinct than the RGO and HM Nautical Almanac Office. During a visit to the Cape in December 1958, Woolley took the opportunity to discuss in detail with Stoy the relationship between the two observatories with special reference to co-operation in astronomical programmes and the interchange of staff. Having studied the technical and administrative implications, Woolley and Stoy sent a joint letter to the Hydrographer on 5 January 1959. stating that they considered ‘it essential that a close organisational link should be set up between the two Admiralty Observatories as soon as possible.’ proposing that ‘the Royal Observatory at the Cape should stand in the same relation to the Astronomer Royal as does H.M. Nautical Almanac Office.’ In their letter, they went on to list the various advantages that the arrangement would bring.

For Greenwich, the advantages were clear. Woolley got access to something he and his staff (particularly Eggen) most desperately wanted – a large modern telescope in the form of the 1.8m Radcliffe Reflector and with it the opportunity to access the unique opportunities in astrophysical research that the southern skies presented at that time. It would also give access to the soon to be completed 40-inch Elizabeth telescope which was then under construction.

For the Cape, the advantages were rather less tangible. Four were listed: more frequent and thorough discussions with Greenwich; a means of overcoming the difficulties being  experienced in staffing the Observatory; ‘Certain advantages’ in submitting material for publication and a greater opportunity for a quicker assimilation of theoretical and technical improvements which were being continually developed in Britain.

For both observatories there would be the ability to undertake all-sky programmes more completely than had hitherto been possible.

Whilst these were the stated advantages, Woolley may well have developed the thought that with the Cape Observatory more under his control, it would be easier to make the sacrifices that might be required in the future should his cherished ambition of building a large telescope in Australia ever come to fruition.

The Lords Commissioners of the Admiralty approved the proposal in principle on 21 May 1959, but it took a year for the Hydrographic Department to look at the organisational changes that might be needed. It was suggested that correspondence between the Cape and the Hydrographer’s Office would generally be via Woolley; that the Cape’s annual report would be published as part of the Royal Greenwich Observatory Report; and that the Cape Observatory would continue to be funded under a separate head in the Navy Estimates. There was also some teasing out of some of the issues around the interchange of staff.  On 4 May 1960, Woolley was asked if he agreed with what was being suggested. The suggestions became the subject of a draft minute of the Hydrographer of the Navy, a copy of which was sent to Woolley on 31 May 1960 for his approval. The Admiralty then appears to have made a formal announcement of the merger (also described at different times both as an amalgamation and an incorporation).  The exact relationship between the two observatories was never formally set out, nor the implications of the merger fully explored.


The wind of change

The first half of the 1960s brought significant changes on the political front in both countries that were to impact heavily on the newly enlarged RGO.

South Africa declared itself a republic on 15 March 1961, and withdrew from the British Commonwealth (it rejoined in 1994).

In the UK, a Minister of Science was appointed for the first time in October 1959. Soon after, the Advisory Council on Scientific Policy recommended that the first priority for British Astronomy in the southern hemisphere should be the development of the Radcliffe Observatory. On the basis of this recommendation, DSIR made an annual grant to the Observatory. Then in 1962, the Prime Minister set up a special Committee of Enquiry into the organisation of Civil Science under the chairmanship of Sir Burk Trend. His report published in 1963, resulted in the creation in 1965 of the various research councils including the Science Research Council (SRC) to which both the Greenwich and Cape Observatories were transferred. Writing to Stoy on 25 May, Woolley enthused about the change, stating ‘I think that the change to SRC is a wholly good thing for both our observatories, not only from the point of view of finance but also from the point of view of conditions of service of staff and promotion.’ He went on to say:

‘I have been asked by the SRC to consider a forward look for the next few years, a thing that was never suggested by the Admiralty at all, and I have put down a very large sum in the Estimates for re-equipping the Cape … You will see that it suggests either that the cape should have a 150-inch telescope outright, or that is should have a 100-inch and a Schmidt, that is a big Schmidt like the one on Palomar. I would like … to discuss with you very fully the political situation as regards the desirability of putting further equipment at the Cape or of moving the entire establishment to Australia … .’ (RGO10/735).

Stoy clearly didn’t like the way the wind was blowing, and suggested to the SRC on a number of occasions over the next couple of years that there would be advantages in the Cape Observatory running as an independent unit. The SRC decided that it was scientifically and financially undesirable to fragment further their efforts in the field of astronomy. The 1960 arrangements were therefore continued with the exception that Stoy was allowed to deal directly with the SRC’s London Office on day-to-day accounting and staff matters.


The quest for larger telescopes and the demise of the Cape

From his first arrival at Herstmonceux at the start of 1956 as Astronomer Royal, Woolley was active in promoting the concept of building for the UK, a large southern hemisphere telescope in Australia (where he had just come from), resisting all pressure for the UK to join the proposed European Southern Observatory (ESO) instead. The arguments over how to proceed dominated UK discussions on optical astronomy for the following decade. Although the British had telescopes in South Africa at the Cape and Radcliffe Observatories, an international partner was needed to fund a large telescope. By the 1960s, the political outlook in South Africa had worsened as had observing conditions at both observatories where light pollution was becoming a real problem. If either of the South African observatories was to have a future, the telescopes needed relocating and the long term funding of the Radcliffe telescope resolved. In 1964, the Research Grants Committee of the DSIR was of the view that if a large (150-inch) telescope was ever built, it would be desirable to move the Radcliffe reflector to work alongside it. The DSIR (who by then were making a major contribution to the running of the Radcliffe) were also of the view that the Observatory should be amalgamated with the Cape. Following the formation of the SRC, the Radcliffe Trustees indicted that they would be prepared to sell them their observatory provided it remained in British hands – an offer the SRC refused.

Eventually, in 1967, the UK and Australian Governments entered into a formal agreement to construct a 150-inch telescope at Siding Spring – the Anglo-Australian Telescope (AAT). At the same time the SRC reached an agreement to lease the Radcliffe Observatory for a further seven years, but which time, it was anticipated that the AAT would be up and running.  These commitments having been made, it was felt necessary to examine afresh the future of the South African Observatories in relation to the ATT. The Astronomy Space and Radio Board (ASRB) of the Science Research Council to whom such matters were delegated asked the Astronomy Policy and Grants Committee (APGC) to undertake a review of optical astronomy in the southern hemisphere. A Southern Hemisphere Review Committee was set up and asked to advise whether the South African facilities should be transferred to Siding Spring or a more favourable site in South Africa. The committee visited South Africa in the late spring of 1968. There they discovered some of the drawbacks inherent in operating a single isolated telescope away from the rest of the scientific and UK community, and were anxious to prevent the ATT suffering similarly. They also considered the way the Mount Palomar 200-inch telescope was operated, noting that its real strength came from its powerful array of supporting instruments. Their recommendation was that a British enclave should be set up alongside the ATT and that a 48-inch Palomar type Schmidt instrument should be provided, with other instruments possibly to follow.

In order to meet the cost, they recommended that activities at the Cape should be reduced and discussions initiated with the South African Council for Scientific and Industrial Research (CSIR) about a potential collaborative use of the British facilities there. Stoy was dismayed at what he saw as the abrupt manner of the decision and the secretiveness of the committee that recommended it. He resigned and left the Cape on 20 November 1968, six days before the Committee’s report was first considered by the APGC. He moved to Scotland, taking up the new (and specially?) created post of Deputy Director of the Royal Observatory in Edinburgh with effect from 1 December. He was also made an Honorary Professor at the University of Edinburgh. Stoy’s abrupt departure together with that of his Chief Assistant David Evans ‘cleared the way’ for the committee’s proposals to be put into effect.

Stoy was the last of H.M. Astronomers at the Cape. With his departure, the Cape Observatory became regarded by the SRC an outstation of the RGO. Stoy was replaced by an Officer in Charge – Alan Cousins until the end of the year, and then by George Harding. On 23 September 1970, it was announced that agreement had been reached between the SRC and the CSIR for a joint astronomical adventure covering a minimum period of 15 years, involving the creation of a new observing station at Sutherland and the pooling of manpower and equipment from the Cape Observatory and the Republic Observatory in Johannesburg.  At the same time, it was announced that the new observing station together with the Cape Observatory (as its administrative centre) were to be known as the South African Astronomical Observatory, and would come into operation on 1 January 1972 under the directorship of Woolley who was due to retire as Astronomer Royal at the end of 1971. The 1971 RGO report is at a slight variance with this; stating that a ten-year agreement was signed in December (1971) for the secondment of enough UK based staff to conduct the observing programmes of the new observatory until they could wholly be taken over by astronomers trained in South Africa.

The new Observing station at Sutherland was officially opened in March 1973 by Prime Minister Vorster of South Africa and the British Secretary of State for Education and Science, Margaret Thatcher. Meanwhile, the writing was on the wall for the Radcliffe Observatory. The telescope was sold to the CSIR in 1974 and moved to Sutherland where it recommenced operations in 1976.

The Radcliffe Observatory in 1974. Photo courtesy of Robin Catchpole


The Board of Visitors

Unlike the RGO, the Cape Observatory had no Board of Visitors or equivalent body. Although initially it had had the Board of Longitude behind it, this link was lost when the Board of Longitude was abolished in 1828. The idea of setting up a Board of Visitors was discussed by David Gill (H.M Astronomer at the Cape) with William Christie following the latter’s appointment as Astronomer Royal in 1881. Gill left the matter in Christie’s hands. For whatever reason, it came to nothing. In 1952, a suggestion was made that a Local Board of Visitors should be established. The matter was discussed on and off, over the next few years. When Woolley was consulted on his views by the Hydrographer in 1957, he was unenthusiastic, not least because ‘they might well be inclined to advocate warmly the spending of money which they were not themselves called upon to provide’ (RGO9/406). A Local Board was never established. As a result, when the Cape Observatory was amalgamated with Greenwich, the Greenwich Visitors began to work on the assumption that their remit had been extended to the Cape.

Following South Africa’s withdrawal from the Commonwealth, the Visitors made enquires about the legal rights of occupancy of the Cape Observatory. They were told that it did not depend on a Commonwealth connection and that although the Union Government held the freehold of the Observatory site, there was a simple bilateral agreement reserving the use of the site to the Admiralty for as long as it wished. With that issue apparently settled, the Visitors belatedly turned their attention to their new responsibilities regarding the Cape.

At their meeting in June 1961, they asked the Admiralty to provide facilities for a small committee to visit the Cape for the purpose of inspection at least once every five years. By June 1962, this had been agreed in principle subject to a) securing funding and b) a determination of the exact status of the Observatory before a delegation of Visitors made an official inspection under direct authority of the Crown in what was now a country outside the Commonwealth.

The perennial question then arose of whether or not the Royal Warrant by which the Visitors were constituted would need amending in light of their new area of responsibility. That no such amendment had been made when the Nautical Almanac Office had been amalgamated with the Royal Observatory, Greenwich in the 1930s suggested it wouldn’t, but the circumstance were different and would need investigation. But before such investigations might commence, the exact legal status of the Cape Observatory had still to be clarified.

The Visitors made their first, and as it turned out, only inspection of the Cape Observatory in April 1963. By the time the Board next met in June that year, they were told that no progress had been made in establishing whether or not the Royal Warrant needed amending as a result of the amalgamation. But by then there were other reasons why the Warrant would need amending in the near future. This was the impending reorganisation under which it was proposed that the Observatories at Herstmonceux and the Cape would both be transferred to the soon to be formed Science Research Council. Contol of both Observatories passed into its hands at the time of its formation in 1965. The Royal Warrant was duly amended – not to set out a revised role for the Visitors, but to abolish them completely.

With the Cape Observatory no longer in the hands of the Admiralty, it would be interesting to know if the Cape site remained legally occupied since the advice given to the Visitors when South Africa had withdrawn from the Commonwealth was that it was reserved only for the use of the Admiralty (rather than any other British institution). The Visitors do not appear to have discussed the matter during the transfer process, despite parallels at Greenwich some ten or so years earlier. Then, the Admiralty had hoped to put the Greenwich buildings to alternative use following the astronomers’ departure to Herstmonceux, but had subsequently discovered to their chagrin, that the Royal Warrant under which they occupied the site allowed them to use it only for Observatory purposes. 


Telescopes and instruments aquired between 1959 and 1970

The Elizabeth telescope is a 40-inch reflector, conceived in 1953 (hence the name), and ordered from Grubb Parsons in 1958. It was housed under the old Yapp Dome that had been shipped out from Greenwich, and became operational at the end of 1963. It was formally opened by the British Ambassador Sir Hugh Stephenson on 1 May 1964. When it was moved to Sutherland, the Cassegrain f-ratio was changed from f/20 to f/16. Had the link up with CSIR not gone ahead, the telescope might have ended up at the Northern Hemisphere Observatory instead.

Dating from 1939, the 30-inch Steavenson Reflector is named after its original owner WH Steavenson (1894-1975), who gave it to the Royal Observatory together with the framework of the dome in 1960/61. By June 1962, it had been erected at the Cape and completely overhauled, the space under the dome providing two much needed offices. A secondary mirror was purchased from Messrs. Cox, Hargreaves and Thompson with a view to providing a folded cassegrain focus and using the telescope for photoelectric photometry, which it was planned to do this in the infra red. The conversion work was completed by June 1963, though it was still possible to use the Newtonian focus when required. At the same time, a slow-motion motor was fitted. When the Cape Observatory was transferred to the Combined South African Observatories, the telescope was moved initially to Herstmonceux and then to Spain.

A Multiple Refractor Housing (MRM) was set up in 1962 on which the various cameras that had until then been attached to the Astrographic and McClean telescopes could be mounted.

A number of instruments were sent out to the Cape from Greenwich. These included a Dallmeyer equatorial mount and two Shortt Free Pendulum clocks in 1959, the Danjon Prismatic Astrolabe in 1964 and a kinetheodolite in 1967 for observing artificial satellites. The astrolabe was sent for a special program to check the systematic accuracy of the fundamental system of star positions between -4º and -64º. Observations of about 1000 stars selected from the ‘bright star’ list of the SRS project were made between 1965 and 1969. A by product of this work was a determination of the latitude and longitude from each night's observations, the results of which were reported to the International Polar Motion Service and the Bureau International de l'Heure.