Royal  Observatory at the Cape of Good Hope

Also referred to as the Cape Observatory
1820 – 1968

Photo Gallery:
Establishing the Observatory
Planning the Observatory
Early Years
Developing the Observatory
World Class Establishment


Current Information:
Current  Information:
The Current Information section is not relevant as the institution  does not exist anymore  as the Royal Observatory at the Cape of Good Hope. An amalgamation occured with the
Republic and Radcliffe Observatories to form the South African Astronomical Observatory (S.A.A.O.) This original terrain now houses the headquarters for the S.A.A.O., and some of its instruments were moved to Sutherland.
Latitude:  33degrees 56′ 03.5″ South
Longitude: 1h 13m 54.6s East

In Brief:

Noted  for:

  1. The first permanent Astronomical Observatory in the Southern Hemisphere.
  2. The first permanent Scientific Institution in the Southern Hemisphere.
  3. Henderson made extremely accurate deduction of the distance to Alpha Centauri. [Laing, p. 10.]
  4. Henderson made nearly ten thousand measurements of star positions. These constituted the first large body of accurate fundamental positions in the Southern Hemisphere. [Warner-Astronomers, p.32.]
  5. Members of the Observatory pioneered astrophotography. [Gill]
  6. Reversible Transit Circle [1st of its kind and model for all circles of this type to follow. Designed by Gill.]
  7. The Royal Observatory was regarded as the main source of scientific information in the Cape Colony. Besides its astronomical work it provided the standard time and was the custodian of the standard set of weights and measures. The Observatory also recorded weather information and holds the longest set of rainfall measurments in South Africa dating back to 1841. [Glass-Rainfall, p.78] 
  8. In 1861 the practice was started to drop timeballs at various remote locations from a telegraph signal originating from the Observatory. This is possibly the first instance in Southern Africa that an object was remotely controlled in Southern Africa. See Time SIgnals
  9. As railways and telegraph lines spread in Southern Africa the need for standardized time became essential.  Principal Towns had two clocks, one for local time and the other for Railway time, which was also known as “Observatory time”. The Observatory came into existence in order to provide a time signal to navigators and this developed into the Observatory becoming the time standard for the Cape Colony, and later on for Southern Africa. This situation ended in 1903 when South African Standard Time (SAST) was fixed to thirteenth Meridian (GMT + 2 hours) [“How Union Fixed Standard Time”] The Transvaal Meteorological Department took over the role of Time Keeper. See Johannesburg Observatory.Following below are some of the reasons of existence / achievements of the Observatory:Published as part of Sesquicentennial (150 years) celebrations,  1970.
    [Laing, pp. 3 -7.]
  • “Created originally by the Admiralty to extend to the Southern Hemisphere the astronomical and navigational work of the Royal  Greenwich Observatory…”
    Chairman of Science Research Council (RSA) – Prof. Sir Brian Flowers
  • “… amassed a wealth of information about the southern stars.  It is not too much to say that we should know very little about the southern stars if it were not for the splendid labours of  this famous Observatory”.
    Astronomer Royal – Sir Richard Woolley
  • “… tradition of excellence … beyond its immediate fields of  interest … as is shown by the part played by a number of  its directors on the building up by professional scientific activities and in the general advancement of science in South Africa in general.”
    President of CSIR (RSA) – Dr. S.M. Naude
  • “Until recently it alone was responsible for producing the fundamental  data on southern stars, and due to its versatility has maintained a continuous output of precise, and therefore useful, results.”
    President of International Astronomical Union – Prof. O Heckmann
  • “Eight successive directors of the Observatory were Fellows of the Royal  Society and the Society is proud of the part they played in  the extension of astronomical frontiers.”
    President Royal Society – Lord Blackett
  • “It  was in 1908 that Sidney Hough became the first President  of our Society and since those early days there has been close  co-operation between our two bodies to our mutual benefit.”
    President Royal Society (RSA) – Dr. G.G. Campbell
  • “Sir David Gill, was the first President of our Association in 1903”
    President S.A. Association for the Advancement of Science –  Prof. I.D. MacCrone
  • “I recall, inter alia, that Dr. R.H. Stoy, C.B.E., Her Majesty’s  Astronomer at the Cape from 1950 – 1968, was Honorary Professor  at this University. Under his guidance and with the facilities  made available, U.C.T. has been able to offer the only  full time university training in Astronomy in Southern Africa.”
    Principal and Vice-Chancellor of the University of Cape Town – Sir Richard Luyt
  • “The Trigonometrical Survey Office of the Republic of South  Africa can be said to have had its origin in the Royal  Observatory at the Cape and is justly proud of this association.”
    Director of S.A. Trigonometrical Survey Office – Mr. W.v.B. Smith
  • “In  the early days it was of primary importance that the chronometers on the ships on Table Bay be set correctly. To assist navigators in this way was really the reason for the establishment of the Observatory. Today we cherish the Noon Day Gun!”
    His Worship the Mayor of Cape Town – Dr. Jan Dommisse
  • “In  the 19th century observations at the Cape Observatory were of paramount interest to the sea surveyor, providing as they  did an accurate longitude of the Secondary Meridian on which were  based the charts of the whole of Africa south of the equator. … did much to further geodetic surveying in Southern Africa  and the carrying of longitude by ship borne chronometer traverses  in the Indian Ocean.”
    Hydrographer of the Royal Navy – Rear Admiral G.S. Ritchie
  • “…nearly every working astronomer makes continuous use of the almanacs and the reference catalogues of positions, proper motions, radial velocities, spectral types, magnitudes, colours and parallaxes  in which most of the Cape work is incorporated.”
    Prof. R.H. Stoy – formerly Her Majesty’s Astronomer at the Cape


  • Due  to a request made by the British Admiralty the Royal  Astronomical Society of England decided in 1820 to establish an observatory at the Cape of Good Hope.
  • The  Directors were called His / Her Majesty’s Astronomer at the  Cape of Good Hope. This was to be the first permanent Astronomical Observatory in the Southern Hemisphere.
  • The  Royal Observatory, Cape of Good Hope, existed between 1820 (1st instrument  installed in 1828) and 1968. Over the timespan of 148  years there were nine directors (six were Cambridge men) and  all of them were men of great achievements, although not all their great achievements were at the Cape.
  • Light pollution is an International problem, and in the 1960’s three of South Africa’s Observatories were badly affected by light pollution. They were the Cape Observatory (Cape Town), Radcliffe Observatory (Pretoria) and Republic Observatory (Johannesburg). By an agreement between the South African CSIR and the British Science Research Council (23 September 1970), a new facility was created away from light pollution at Sutherland in the Karoo. The main instruments from the Cape and Republic Observatories were moved to the new sight, and the Cape Observatory grounds became the headquarters for the new South African Observatories (today the South African Astronomical Observatory S.A.A.O.)
    Radcliffe Observatory closed down, and its 74-inch telescope was bought and moved to Sutherland.
    Thus the original Royal Observatory at the Cape of Good Hope metamorphed into a new entity, the
    S.A.A.O., which for reasons of convenience and space will be dealt with in this website as a separate establishment.

Historical background:
Note: Due to the amount of material available, the historical background for the Cape Observatory has been moved to a separate page. Click here to go to the historical page.


List of Directors at the Cape of Good Hope:

Some confusion exists about the title for the Directors. Early documents refer to the person in charge as the Astronomer Royal  at the Cape. By 1855 the title became His / Her Majesty’s Astronomer at the Cape of Good Hope. [Laing. p. 27.] For reasons of space the title Director will be used.

  • Fearon Fallows (1821 – 1831) He chose the site, organised  the building of the facilities, and set up the first instruments. He died in 1831 (age 42) and was buried on the Observatory grounds.
  • Thomas Henderson (March 1832 – May 1833?) Henderson did not stay long. He detested the Observatory and referred to it as the “dismal swamp”. Henderson made a very accurate deduction of the  distance to Alpha Centauri.
  • Thomas Maclear (1834 – 1870) He put the observatory on a firm scientific footing by making lots of observations, but he did not interpret  the data. He also re-measured De La Cailles Arc of the meridian.
  • Edward Stone (1870 – 1879) He did a lot of reductions based on Maclears  observations.
  • David  Gill (1879 – 1907) when Gill took over the Observatory was outdated. Gill set out to modernise the facility, and when he retired the Cape Observatory was one of the finest and best equipped observatories in the world. He pioneered astrophotography,  and did an incredible amount of work towards establishing photographic  catalogues of the Southern Sky.
  • Sydney Hough (1907 – 1923) Hough completed a lot of Gills programmes.  “His directorship was known not as a period of change, but  one of achievement” (Collins p.79.) World War One caused a lack of funds to maintain equipment.
  • Harold Spencer-Jones (1923 – 1933) He concentrated mostly on the proper motions of stars. The greatest problem he faced was lack of money due to the great depression, but he still managed to raise funds, completed some of the projects that Gill started,  and he also started new projects. Spencer Jones also recruited  astronomers locally.
  • John Jackson (1933 – 1950) His period of directorship was hampered by World War Two, but he still managed to do valuable work,  especially concerning Stellar Parallax.
  • Richard  Stoy (1950 – 1968) Stoy was the last director of the Royal Cape Observatory (also the last to be called H.M. Astronomer to  the Cape of Good Hope) He was also one of the most effective and  universally popular directors. On retirement in 1968 some of the mayor projects were almost complete, and there were no arrears in publications, a state of affairs almost unknown in  the 148 years of existence of the Cape Observatory.
  • George Harding (1969 – 1973) Mr Harding was not a director,  but “officer in charge” during the change over period from Cape Observatory to Combined South African Observatories  (Sutherland). He became deputy of S.A.A.O. under van der Riet Woolley.

Assistant  Directors:

  • William Meadows [Lieutenant] (1831 – 1835):
    Meadows was the first Assistant Director at the Observatory. Initially Fallows as director started the Observatory with no Assistant Directors. Fallows had assistants, but they did not however had the title of Assistant Director. Their names were James Fayrer, Patrick Scully, William Ronald and James Robertson, see Fallows: (Establishing the Observatory). Meadows was appointed by the admiralty as Assistant Director, and left England after Fallows died. In England they received word that Fallows was very sick, and only when Meadows arrived in Cape Town did he learn of Fallows death. On paper Meadows was assistant to Fallows, Henderson and Maclear, but in reality he was assistant only to Henderson and Maclear.
    Note: According to Warner, that upon hearing of the death of Fallows the senior officer at Simon’s Town, Commodore Schomberg, put his Chaplain, Reverend John Fry, in charge of the Observatory. [Warner – Astronomers, p.30]

Chief  Assistant:

[Laing,  p. 18.] (I presume a name change occurred from Assistant Director to Chief Assistant)

  • C. P. Smyth (1835 – 1845) Later Royal Astronomer for Scotland.
  • W. Mann (1847 – 1872)
  • W. H. Finlay (1873 – 1897)
  • S. S. Hough (1898 – 1907) Became director of Royal Observatory, Cape of Good Hope.
  • J. K. E. Halm (1907 – 1927)
  • H. Horrocks (1927 – 1935)
  • R. H. Stoy (1935 – 1950) Became director of  Cape Observatory.
  • David  Evans (1950 – 1968) Evans was chief assistant to Stoy. He also spends a lot of time observing at Radcliffe Observatory due  to an agreement between Cape and Radcliffe Observatories.


  • R.T.A. Innes, who was destined to become the director of the Republic  Observatory, left a profitable wine merchant career in Australia  to become a low paid secretary – cum – librarian – cum – accountant at the Cape Observatory during the time of the directorship of Gill.
  • Alan Cousins (1903 – 2001) He joined the Observatory as an amateur astronomer, and remained there the rest of his life, even after retirement.
  • Joe  Churms (1926 – 1994):
  • Alexander  Menzies (1905 – 1988): He started working for the Observatory fresh out of school, as an “unestablished computer”, and he remained there for 44 years until his retirement.


Research/public  service

  • Positional Astronomy. Determination of stellar distances (or parallaxes)  was a traditional research method at the Cape, since most pre-photographic  measurements of the southern sky were made here. In the 1830’s  the photographic determination of stellar distances by the direct trigonometrical method were made at the Cape. Since 1925 until the transformation of the Cape Observatory, when newer photographic  methods were introduced, more than 1 800 stellar distance determinations  were made. [Laing, p.30.]
  • Stellar  Photometry. Photographic maps were produced of the southern  sky.
  • Solar  Photography.
  • Spectroscopy.
  • Satellite  Tracking.
  • Time Service:
    One of the reasons for creating the observatory was to help with navigational problems. This meant the creation of a time service to help ships determine their longitude. The time service was set up before the observatory was built.
    Fallows, the first director of the observatory initiated the first time service from the property that he rented at the time, namely Zorg and Lust, in Gardens, a property now occupied by the Ladies Christian Home. Approximately in June 1823 Fallows shone an Argand lamp in the evening and doused it at a pre-arranged time. [Warner – Astronomers, pp.9 – 10.]  (Was the time service discontinued when Fallows moved from Zorg and Lust to the Observatory grounds?)
    Early in 1833
    Henderson started a new time service. He climbed onto the roof of the observatory and at an advertised time fired a pistol. (black charge only, no bullet in the barrel) The flash was bright enough for sailors to observe with a telescope from the harbour. [Warner – Astronomers, p.32.]
    Maclear became director he improved on Henderson’s pistol by firing a cannon from Signal Hill (a hill overlooking Table Bay) at the advertised time of 9 p.m. (21h00). Another addition was made when in September 1836 a time ball was taken into use. The principle of the time ball is that a very large, visible (brightly painted) round object was hoisted up a pole. At an advertised time the ball was dropped and this was the signal for navigators and other interested persons to set their chronometers (watches) to the correct time. This came about because a new Admiral, Patrick Campbell, was appointed to the Cape. His brother-in-law was Captain Robert Wauchope, the inventor of the time ball. English Astronomer James Pond took up Wauchope’s idea and the first time ball in the world was erected at the Royal Greenwich Observatory in 1833. Campbell persuaded Maclear to follow suit but due to the reluctance of the Admiralty to spend money the time ball was erected at the Cape only in 1836. [Warner – Astronomers, p.47.]
    By 1853 Cape Town has expanded so much that the ships in the harbour could not see the time ball on the Observatory grounds anymore. Two new time balls were added to the time service, one at Signal Hill and the other at Simon’s Town. By 1861 telegraph lines were installed in the Cape Colony and the drop of the balls were now done electrically from the Observatory. Batteries had to be installed and were housed next to the Mertz building. In 1865 another time ball was added to the system, in Port Elizabeth, 500 miles (+/- 750 km) distant, in “a feat without parallel in the electric work.” [Warner – Astronomers, pp.63 – 65.]
  • Magnetic Observatory:
     In 1841 the Magnetic Observatory (and Meteorological Observatory: See below.) was established on the grounds of the Cape Observatory. The was run by the Royal Artillery. Thus administratively it was totally separate to the Astronomical Observatory but they shared the same locality. Their commanding officer was Lieutenant Frederick Eardley-Wilmot. They build cottages for accommodation, huts to house the instruments, and a “Wind Tower” for the Meteorological section. In 1846 the Observatories were transferred to the Admiralty and Maclear had to continue their work. Maclear nevertheless bemoaned the time the new responsibilities took away from his other duties. Less attention was paid to the magnetic work after 1857 as Maclear steered the resources more in the direction of Astronomical work. After Maclear’s retirement in 1869 no further magnetic work was carried out, but meteorological observations continued. [Warner – Astronomers, pp.59 – 60.]
    In approximately 1874 new magnetic equipment was send out from England. Stone was then director of the Observatory and he took the equipment along on an expedition to view the total solar eclipse of 16 April 1874. He made the first magnetic observations of Namaqualand. [Warner – Astronomers, p.76.]
    H.M.S. Challenger was on the first major oceanographic expedition around the world and the second in command of the vessel was Jack Maclear, son of Thomas Maclear. In 1874 the vessel arrived at the Cape and Jack was granted permission to use the magnetic observatory to make measurements. [Warner – Astronomers, pp.76 – 77.]
  • Meteorological Observatory:
     Was initially part of the Magnetic Observatory. See above. A “Wind Tower” was built to house an anemometer. In time these observatories were incorporated into the astronomical observatory, the magnetic observatory was neglected and by 1869 ceased to exist, but meteorological work continued.  [Warner – Astronomers, pp.59 – 60.]



First  instruments installed at the end of 1828.


Other  instruments


Pictorial  Sources:

Print  / Lithograph / Engravings:

  • S.A.C.H.M. acquisition. no. 1101
  • Illustrated  London News 21/3/1857 (Museum Africa MA 834)
  • Illustrated  London News 17/6/1865 (Museum Africa MA 835)
  • Illustrated  London News 27/8/1892 (Museum Africa MA N/A) (11 illustrations  of staff / instruments / buildings)
  • Bowler T.W. (Museum Africa MA 3101) -Lester O. (Museum Africa MA 50/1401)
  • Collins, P. & Moore, P.; Astronomy in Southern Africa, p.77. Sketches at the Cape Observatory, from The Graphic Aug 27 1892 (Africana Museum)

Paintings / Sketches:

  • Bowler T.W. (Museum Africa MA 832)
  • Bowler T.W. (Museum Africa MA 49/1343)
  • Bowler T.W. (Museum Africa MA 53/75)
  • J.T. Haverfield (Museum Africa MA 60/1425 [pencil sketch on reverse side])
  • Le Camp E.W. (Museum Africa MA 62/1181[15])
  • (Museum Africa MA 58/730)
  • (Museum Africa MA 69/2494)
  • (Museum Africa MA 72/3)
  • Collins, P. & Moore, P.; Astronomy in Southern Africa, p.68. Observatory  1865 (Africana Museum)


  • Bowler T.W. (Museum Africa MA 66/2221)
  • Museum Africa computer keyword search of Cape Archive / Library of Parliament / S.A. Library. 4 photo’s, one of which is staff photo with D.Gill, J. Hunt and S.S. Hough.
  • Moore,  P. & Collins, P., Astronomy in Southern Africa, p.46. “Henderson’s  Dismal Swamp 1911” (Africana Museum)


  •   Government Gazette – 1903 Announcement of the adoption of a standard time zone: Cape of Good Hope Government Gazette – 1903, p.443.
  • Gill, D.: A History and Description of the Royal Observatory, Cape of Good Hope. Neill and Company, Edingburgh, 1913.
  • Glass, I.S.: The Royal Observatory at the Cape of Good Hope; History and Heritage, Megadigital, Cape Town, 2015.
  • Glass, I.S.: Proxima, the nearest star (other than the Sun). Mons Mensa, 2008.
  • Glass, I.S, The Royal Observatory Rainfall Records. MNASSA, Vol 77, Nos 5 & 6, 2018 June.
  •   “How Union Fixed Standard Time”: Sunday Times, Johannesburg, Transvaal: April 25, 1926.Laing,  J.D. (ed.), The Royal Observatory at the Cape of Good Hope 1820 – 1970 Sesquicentennial Offerings. pp.3 – 44.
  • Moore, P. & Collins, P., Astronomy in Southern Africa, pp. 43 – 91. (General Source)
  • Smits, P., A Brief History of Astronomy in Southern Africa. (Unpublished)
  • 100th  Anniversary of Electricity at R O Cape, MNASSA, Vol. 47, Nos. 11 & 12, 1988, December.
  • MNASSA,  Vol. 4
  • 8, Nos. 5 & 6, 1989, June, p. 59.
  •   “Unified Time in the Union”: Sunday Times, Johannesburg, Transvaal: June 13, 1926.
  • Warner, B., Astronomers at the Royal Observatory Cape of Good Hope.


This is the principal depository for all the early Government records  and thus contains official correspondence concerning the visits of Kolbe and Lacaille. The records of the Colonial Office and of Government House also contain correspondence connected with the  establishment of the Royal Observatory.
Almost all documents relating to the business of the Royal Observatory prior to Gill’s arrival in 1879 have been sent to the Archives at the Royal Greenwich Observatory. Exceptions are…
-The complete correspondence, finances, etc., of the Observatory during the period 1879-1929 are bound in 56 volumes in chronological  order and separated into subjects. Extensive collections of documents from 1929 to date are extant but are not conveniently ordered or  indexed.
-All of the original observing books back to 1834 are stored.
Material relevant to the Cape Observatory is shelved separately  in the Archives of the Royal Greenwich Observatory and contains some 112 bound volumes and 32 boxes. These papers derive from three  sources:
(a) material sent home contemporaneously from the Cape,
(b) correspondence and papers of the Astronomers Royal (Airy and Christie), and
(c) material transferred from the Cape c. 1960.
(a) and (b) are in general bound volumes taken from the Collection at the RGO and have classification numbers (c4, vols. 1-33) assigned by Airy, or boxes NI-N5 of the Christie papers. The bulk of the  material is, however, uncatalogued and unclassified.
-Miscellaneous notes, including printed diary (astronomical notes) notes for a history of the Cape Observatory (principally of Henderson’s  own work) and an inventory.
-Official correspondence: Simon’s Town (1850-69), Admiralty (1853-70), Colonial Government (1861-72), General (1844-69), II vols. Weekly registers (reports of work done), 1849-60.
-Christie papers (1879-1909): correspondence with Cape Observatory (6 boxes) on Appointments, Instruments, Surveys and Publications.

Interesting Links: