Gill D.


GILL, David [KCB; FRS][Sir]Professional Astronomer

Born: 1843, Aberdeen, Scotland.
Died: 24 January 1914, London, U.K.


In brief :
Famous for:
Director of the 
Cape Observatory:  1879 – 1907.
Pioneer of Astro photography.
Gill and Mouchez, the director of the Paris Observatory, convened the world’s first international astronomical meeting in Paris—the “astrographic” meeting in 1887—  which Culminated in the Carte du Ciel Project.
Speciality was angular distance measurements. He made some of the worlds most accurate measurements before the space age.
Designed the 
Reversible Transit Circle. Most transit manufacturers have since copied his design.
Gill award. This is South Africa’s highest award in the field of Astronomy (named after him).
David  Gill was one of the most remarkable astronomers in the history  of Southern African Astronomy.  When Gill took over,  the Observatory was outdated.  He 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.  Gill pioneered astro photography and did an incredible amount of work towards establishing photographic catalogues of the Southern Sky. The projects that Gill started still kept two directors preceding him busy.  He was also a remarkable person outside of the field of astronomy, as the personal section attest.

Historical background :
David Gill became interested in Astronomy before he was ten years of age, thus before 1853. (Born 1843: Look personal section.) [Moore p. 72]
1863:  In his spare time he helped Prof. Thomson at Kings College to set up an old transit instrument and to establish an accurate time server.
1866:  Gill built a small observatory with a 
12-inch telescope that he made himself.
After school Gill went into the family business & was a clock and watchmaker for two years -some of the time spent on  the European Continent. During this time he acquired a feeling for precision instruments, knowledge of business methods and foreign languages, which were to be useful to him later as an astronomer. [Laing, p. 12.]
“On  18 May 1869, at a time when photography was still in its  experimental stage, Gill took a picture of the Moon. It can safely be said that it was this achievement – the photograph  was an excellent one, even by later standards – which drew attention  to the young amateur and started him off on the career which was  to bring him international fame, and provide astronomers all over the world with a priceless new research tool.” [Copied from  Moore p.73.]
(+/-  1870) Lord Lindsay of Dun Echt (13 miles from Aberdeen)  saw Gill’s photograph of the moon.  He was an aristocrat  who used his money to build a private observatory, equipping it  on a lavish scale with instruments finer than many of those available in Government Observatories. After meeting Gill he offered him  the post of director. [Laing, p. 12.]
At  Dun Echt he made some of the best ever measurements of angular  distances to stars. “One of the instruments provided  for his use was a 4-inch heliometer. As Gill’s future observational measurements were to be made largely  with this type of instrument, it may be as well to say something  about its structure and use. In a heliometer, the object glass  is cut in half, so that one half may be made to slide past the  other, giving a double image of the object under study. It is used to measure very small angular distances as seen through the  telescope. Gill’s great skill in the use of precision instruments,  which was innate and which had been further developed during his  watch making days at Besancon, helped him to make this device peculiarly his own) and indeed his results remained among the best ever obtained right up to the era of space-probes. After  a night spent in using the heliometer, Isabel used to say that  he would come into the house shouting and singing “as if  he had gone daft”! [Copied from Moore pp. 73 – 74.]
1874:  Gill went with Lord Lindsay to Mauritius to observe the 
transit  of Venus. This was a privately sponsored expedition to observe the transit, and Gill was the chief observer. The results were disappointing. [Sheenan p. 35]
1877:  Gill joined the Royal Astronomical Societies’ sponsored expedition  to the Ascension Islands. He observed the opposition of Mars and calculated a very accurate sun / earth distance. (Astronomical Unit)  His value was within 0.2 percent of the modern accepted value. [Sheenan, p. 36; Koorts – British, pp. 55 – 56.]
1879: Due to Lord Lindsay’s prompting, Gill was appointed Her Majesty’s  Royal Astronomer (Director) at the Cape of Good Hope.  Before he took up his post, he extensively travelled Europe in order to meet some of the world’s foremost astronomers. He visited Paris, Leiden, Copenhagen, Helsinki, Pulkova and Strassburg.
1879 (June): Gill arrived in Cape Town.
1881  – 1883: Gill privately acquired the 
Dun Echt Heliometer from Lord Lindsay.
Gill’s  tasks at the Cape were to: [Laing, p. 12.]
-wipe out all arrears of reductions.
-recondition existing instruments.
With  the R
epsold Heliometer, Gill (with co-operation from Northern Hemisphere observations) determined the solar parallax of three minor planets, Iris, Victoria  and Sappho.  The value that he used of 8″. 80 were used in the computation of all almanacs, up to 1968 when radar echoes methods and data from the mariner probe refined the value to 8″. 794. [Laing, p. 13.]
Gill  used the Repsold Heliometer to measure the distances to a number of Southern stars. His accuracy was later confirmed by photographic observation methods.  [Laing, p. 13.]
In 1882 another 
transit of Venus took place and South Africa was idealy placed to observe the event. The British appointed Stone, previous director of the Cape Observatory, to organise the British expeditions. As part of British efforts the transit was observed from four sights in South Africa, and there was also an American expedition to Wellington. Gill was placed in charge of organising the expeditions locally. [Koorts – British, p. 41, p. 43; Koorts – Huguenot, pp.199 – 200.] To help solve the timing problems (accurate timing is essential) Gill pionered the placing of observing sights next to telegraph lines. [Koorts – British, p. 41.]
In  1882, 
Finlay, an astronomer at the Cape Observatory discovered a bright comet in the southern sky, which became  known as the ‘Great Comet of 1882′..  By this time  the ‘dry plate’ cameras were newly introduced.  Gill, remembering his Moon photograph of 1869, invited a local photographer, Mr Allis and they fastened a portrait camera to the clock-driven equatorial telescope.  They took several photos and the results were astounding. The photographs showed a good image of the comet, but the background stars were also shown with absolute  clarity and sharpness. [Koorts – British, p. 51.] The more he studied the photographs, the  more he realised the use of photography for making star-maps down  to very faint magnitudes. Gill sent the results to a few institutions,  including the Royal Astronomical Society, Royal Society, and the  Paris Observatory. Gill also ordered a larger lens from Dallmeyer,  the famous optical worker.   [Moore pp. 75 – 76.; Smits]
These photographs of the comet would motivate Gill to start one of the most ambitious projects of his career. The result was the famous 
CPD or Cape Photographic  Durchmusterung, which extended a Northern Hemisphere survey, the  Bonn Duchmusterung, down to the South Pole of the sky. The finished  catalogue gives the brightness and approximate positions of nearly  half a million southern stars.  [Moore p. 76]
Carte  Du Ciel. The Paris Observatory was interested in creating  it’s own map of the sky, and enlisted the help of Gill. “Even while work on the CPD was going on, a larger and even  more ambitious project was put in hand by the Paris Observatory.  This was nothing less than a photographic chart of the whole sky, showing stars down to the fourteenth magnitude. In addition there  was to be a catalogue giving the precise positions of all stars down to the eleventh magnitude – more than a million stars altogether.   A scheme of this kind could be carried through only with the co-operation  of many astronomers and many observatories. As the acknowledged “father of astrography“, Gill was prominent both in the organising and the carrying-out of this great work. His many friendships among astronomers, made or strengthened during  his “grand tour” before he had set out for the Cape,  now stood him – and the Carte du ciel, as the project was  called – in good stead. A major portion of the work was carried out at the Cape Observatory, and a fine new telescope, the astrographic  refractor, was acquired. Yet in spite of the devotion of Gill and his colleagues, work on the Carte du del was not completed until a few years ago. The whole concept was simply too big for  late-19th century facilities.” [Copied from Moore p. 79]
1900 (May 24): Gill was knighted.
Gill  designed the reversible transit circle, which has become the pattern for most of the transit circles made since.
Gill  achieved a variety of impressive things outside of the field of Astronomy.  See “Personal Aspects.”
1906: Due to ill health, Sir David and Lady Gill retired in London. (Note: According to Moore p. 91, Gill was Director  until 1907.  I presume he was considered Director until a replacement was appointed) career

  • 1869: Gill took photo of moon.
  • 1872 – 1876: Director of Dun Echt Observatory. [Laing, p. 12]
  • Made extremely accurate measurements of angular distanced to  the stars.
  • 1874:  Visit Mauritius for Transit of Venus.
  • 1877:  Calculate accurate Sun / Earth distance during opposition of Mars.
  • 1879 – 1907: Director of Cape Observatory.
    -Chief Assistant: 
    Finlay 1879 – 1897
    Hough 1898 – 1907
  • 1882:  Photo of Comet.
  • CPD catalogue.
  • Carte Du Ciel.
  • Design Reversible Transit Circle.
  • 1900:  Knighted.

Born 1843: Aberdeen Scotland.
His  father was a distinguished watchmaker and held a Royal Warrant  as Watchmaker to Queen Victoria.
(+/-  1857) Gill at 14 years of age.  He joined the Dollar Academy, and boarded with the headmaster, Dr. Lindsay, who influenced him  and interested him in mathematics, natural philosophy and chemistry.
Gill  spends two years at Marshall College, Aberdeen as a private student.  (Term denoted to those not intending to qualify  for a degree.)
He  joined his father in the watch making business. Gill spent  one year at Besacon in Switzerland.
1863:  Gill had returned from Switzerland to Aberdeen. He start to become active in Astronomy. (Look Historical Section.)
1870:  Married Isabel Black, daughter of a local farmer. She is described as highly intellectual.
1870:  Started his astronomical career. (Look Historical and Career Section.)
1900 (May 24): Knighted
1906: Sir and Lady Gill returned to London due to ill health (34 De  Vere Gardens, Kensington, London)
1914 (Jan 24): Died. Buried at Aberdeen

Other Personal Aspects:
Avid golfer, and considered as one of the fathers of golf in  Cape Town. [Cape Chronicle, August 2000, Volume 4 Issue 8,  p.8]
First  President of the Owl Club.  He was also the only person to retain the office for several years. [Laing, p. 14]
Active member and President of the South African Philosophical Society. [Gill, Annual address to Members of the SA Philosophical Society, 17 Sept 1902]
1903: Founder and first President of the South African Association  for the Advancement of Science. [Laing, p. 5, p. 13.]
Gill served as the head (unpaid) of surveys for Southern Africa.  He organised various geodetic and boundary surveys  as well as numerous determinations of longitude and latitude of important ports. [Laing, p. 14]
Gill’s most ambitious project was the survey of the 30th meridian.  This was the measurement of the 30th meridian line, stretching from Cape to Cairo, through the Levant and terminating at Nordkapp (Sweden). A chain of triangles forming the backbone of the 30th  meridian would provide the geodetic control for countries traversed by the arc. [Laing, p. 14; Amod, p. 3]
Lord Milner appointed Gill as Scientific adviser to the Governments of the Transvaal and Orange River Colony. He was instrumental  in establishing what was to become the Republic Observatory.  [Laing, p. 14]
Personality:   He had a total lack of self-consciousness.
His voice was very high pitched.

List of Titles and Honours bestowed on David Gill [Gill – title page]

  • K.C.B. (The Most Honourable Order of the Bath, order of British knighthood established by King George I in 172)
  • Knight of the Prussian Order POUR LE MERITE
  • Commander of the Legion of Honour (France)
  • Hon. LL.D., Aberdeen and Edinburgh (Honorary Doctorate)
  • Hon. Ds.C., Oxford, Cambridge, Dublin and Cape of Good Hope. (Doctorate of Science)
  • F.R.S. (Fellow of the Royal Society)
  • Hon. F.R.S.E. (Fellowship of the Royal Society of Edinburgh)
  • Foreign Sec. R.A.S. (Royal Astronomical Society)
  • Correspondant de L’Institute de France (Academie de Sciences) et de Bureau des Longitudes (France)
  • Foreign Member della Realle Accademia dei Lincei, Roma.
  • Foreign Member of the Royal Acadamy of Sciences, Amsterdam.
  • Corresponding Member of the Royal Acadamy of Sciences, Berlin.
  • Corresponding Member of the Imperial Acadamy of Sciences, St Petersburgh.
  • Foreign Member of the National Academy of Sciences, Washington.
  • Foreign Member of the Royal Academy of Sciences, Sweden.
  • Foreign Member of the Societe Hollandaise Nationale de Sciences, Haarlem.
  • Foreign Member of the American Academy of Art and Sciences, Boston.
  • Foreign Member of the American Philosophical Society of Philadelphia
  • Foreign Member of the Italian Spectroscopy Society, Rome.
  • Honorary Member of the New York Academy of Sciences.
  • Honorary Member of the Societe des Sciences de Finlande, Helsingfort.
  • Honorary Member of the Royal Society of Glasgow.
  • Honorary Member of the Royal Society of South Africa.
  • First Honorary Member of the Astronomical and Astrophysical Society of America.
  • Corresponding Member of the Societe Nasionale des Science, Cherbourg.
  • Corresponding Member of the Sociedade de Geographica, Lisbon.
  • Etc.
  • Bruce Medallist of the Astronomical Society of the Pacific (1900).
  • Watson Medallist of the Natiolnal Academy of the United States, 1900.
  • Gold Medallist of the Royal Astronomical Society, 1882 and 1908.
  • Royal Medallist of the Royal Society of London, 1903.
  • Vals Medallist of the Institute of France, 1882 (Acad. des Sciences).


Link to the Telescope Manufacturers.


Link to the Main Bibliography Section and more information about Sources.

Remaining  Artifacts:
Gill Medal. This is South Africa’s highest award in the field of astronomy.
Street named after him. The Republic Observatory street address is Gill St, Observatory, Johannesburg.
Africana Museum  [Laing; Moore p. 72]

  • Amod A, et. al., A History of Geodetic Surveying in South Africa –  Part 1, The Cape Odyssey, Historical Media cc, Cape Town, Aug./Sept. 2002 – Vol. 2 Issue 7, pp. 1 – 9.
  • Gill, D.: A History and Description of the Royal Observatory, Cape of Good Hope. Neill and Company, Edingburgh, 1913.  Gill – ROCGH
  • Koorts, W.: The 1882 transit of Venus and the Huguenot Seminary for Girls; MNASSA October 2003, Vol. 62 nos. 7 & 8, pp. 198 – 211.
  • Koorts, W.: The 1882 transit of Venus: The British expeditions to South Africa; MNASSA April 2004, Vol. 63 nos. 3 & 4, pp. 34 – 57.
  • Laing, J.D. (ed.), The Royal Observatory at the Cape of Good Hope 1820  – 1970 Sesquicentennial Offerings, pp. 12 – 14.
  • Moore  P. & Collins P., Astronomy in Southern Africa, pp71 – 79    (General Source)
  • Sauerman P., A brief history of Golf in the Peninsula,  Cape Chronicle, August 2000, Volume 4 Issue 8, p. 8.
  • Sheehan, J.: The Transit of Venus, Tales from the 19th Century; Sky and Telescope, May 2004, pp. 32 – 37.
  • Smits, P., A Brief History of Astronomy in Southern Africa. (Unpublished)

By Gill:
History  and Description of the Cape Observatory, (Written after his retirement) Gill – ROCGH

-(Colonel Charles Warren: Report to the Under Secretary of State on Proposed Survey of Transvaal 1880 June 7.)
Sir David Gill: MS comments on Warren’s report, 1880.

-Maclear-Mann Papers (Accession No. 515): this extensive accumulation  of manuscripts and correspondence is contained in 139 files. It  derives from presentations made by members of the Maclear family  and from donations from the Trigonometric Survey and from the Royal Observatory, Cape. Although mostly concerning Sir Thomas Maclear and William Mann, a considerable amount of material relates to Sir  John Herschel and to the early history of the Cape Observatory. Excluding miscellaneous files of accounts, testimonials, newspaper  cuttings, etc., the most significant references are:
121 Miscellaneous, including Henderson’s R.A. and Dec. reductions, Stone’s accounts. Gill’s expedition to Ascension Island.


The Archives of this Museum contain extensive correspondence on Museum matters by Sir Thomas Maclear and Sir David Gill, both of whom were Trustees.


-David Gill (1879-1907).
Two boxes and 43 bound volumes of correspondence including letters to and from virtually all of the prominent astronomers of the period and on the particular topics of Chronometers and Time Balls (1879-1900,  4 vols.), Magnetism, Meteorology, Meteors and Seismology (1879-1906, 2 vols.); Geodetic Surveys of Rhodesia (1897-1906), Transvaal (1901-1906)  and the whole of South Africa (1879-1906, 4 vols.); Survey of the  Anglo-German boundary (1896-1906, 2 vols.); British Association visit to South Africa (1905, 4 vols.); Natal observatory (1881-1890); Transit of Venus (1882); Photography (Corona and Southern Durchmusterung).

Related Internal Links:
Royal Observatory at the Cape of Good Hope.
Related External Links:
Historical Astronomical Posts in Britain and Ireland
Encyclopedia Brittannica:
The Bruce Medalists: David Gill



Sir David Gill. Courtesy of Africana Museum, Johannesburg. Source: Moore; Laing.

Courtesy Royal Astronomical Society. Source: Warner, Astronomers

Courtesy Royal Astronomical Society. Source: Warner, Astronomers


Sir David Gill circa 1905. Source: MNASSA 1991, Vol. 50, No. 11, p. 122b.

Sir David Gill circa 1905.
Source: MNASSA 1991, Vol. 50, No. 11, p. 122b.

The Great Comet of 1882, discovered by Finlay. This photo, taken by Gill, was the first ever photograph of a comet. It led Gill to the realisation that phototgraphy can be used as a method to study astronomy, and from this realisation the first photographic star catalogues were made, for example the Cape Photographic Catalogue and the Cape Photographic Durchmusterung. Gill is considered as one of the pioneers of astrophotography.
Photo taken by Gill. Source: Moore.

Gill Medal. This is the highest award made by the Astronomical Society of Southern Africa.

Gill Medal. This is the highest award made by the Astronomical Society of Southern Africa.