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David Gill (astronomer)
Encyclopedia
Sir David Gill FRS (12 June 1843 – 24 January 1914) was a Scottish astronomer who is known for measuring astronomical distances, for astrophotography, and for geodesy. He spent much of his career in South Africa
.
and educated at Dollar Academy
. He spent two years at Aberdeen University, where he was taught by James Clerk Maxwell
, and then joined his father's clock-making business. It would seem that Gill's interests lay elsewhere since after a few years he sold the business, and then spent time equipping Lord Lindsay
's private observatory at Dun Echt
, Aberdeenshire
. In 1874, Gill joined the expedition to Mauritius
to observe the transit of Venus
. Three years later he went to Ascension Island
to observe a near approach of Mars
and to calculate its distance. While carrying out these laborious calculations, he was notified of his appointment to the Cape Observatory, which, over the following 27 years he was to refurbish completely, turning it into a first-rate institution. Gill was a meticulous observer and had a flair for getting the best out of his instruments. His solar parallax observations with a heliometer
and his calculations of distances to the nearer stars, are testimony to his outstanding work. He recruited Robert Innes to the Cape Observatory.
Gill used the parallax
of Mars to determine the distance to the Sun
, and also measured distances to the star
s. He perfected the use of the heliometer. He was Her Majesty's Astronomer at the Cape of Good Hope
from 1879 to 1906. He was a pioneer in the use of astrophotography
, making the first photograph of the Great Comet of 1882
, and one of the early proponents of the Carte du Ciel
project.
The invention of dry plate
photography by Richard Leach Maddox
made Gill realise that the process could be used to create images of the stars and to more easily determine their relative positions and brightness. This led to a massive project in collaboration with the Dutch astronomer J.C. Kapteyn
, and the compiling of an index of brightness and position for some half a million southern stars. The work was published as Cape Photographic Durchmusterung in 3 volumes between 1896 and 1900. Gill also played a leading role in the organising of the Carte du Ciel, an ambitious international venture aimed at mapping the entire sky. He initiated the idea of a geodetic survey along the 30th east meridian stretching from South Africa to Norway
, resulting in the longest meridian yet measured on Earth.
Gill married in 1870, and his wife accompanied him to Ascension Island for his Mars observations. On Gill's retirement in 1906, the couple moved to London
, where Gill served for two years (1909–1911) as president of the Royal Astronomical Society
before his death in 1914. He was buried in Aberdeen.
, volumes xlvi and xlviii, 1881 and 1885). New International Encyclopedia
In 1913 he published A History and Description of the Royal Observatory at the Cape of Good Hope.
Awards
Named after him
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
.
Life and work
David Gill was born in AberdeenAberdeen
Aberdeen is Scotland's third most populous city, one of Scotland's 32 local government council areas and the United Kingdom's 25th most populous city, with an official population estimate of ....
and educated at Dollar Academy
Dollar Academy
Dollar Academy was founded in 1818, which makes it the oldest co-educational day and boarding school in the world. The open campus occupies a site in the centre of the thriving town of Dollar in Central Scotland, less than 40 minutes drive from the two main Scottish cities, Glasgow and Edinburgh...
. He spent two years at Aberdeen University, where he was taught by James Clerk Maxwell
James Clerk Maxwell
James Clerk Maxwell of Glenlair was a Scottish physicist and mathematician. His most prominent achievement was formulating classical electromagnetic theory. This united all previously unrelated observations, experiments and equations of electricity, magnetism and optics into a consistent theory...
, and then joined his father's clock-making business. It would seem that Gill's interests lay elsewhere since after a few years he sold the business, and then spent time equipping Lord Lindsay
James Lindsay, 26th Earl of Crawford
James Ludovic Lindsay, 26th Earl of Crawford and 9th Earl of Balcarres was a British astronomer, politician, bibliophile and philatelist. A member of the Royal Society, Crawford was elected president of the Royal Astronomical Society in 1878. He was a prominent Freemason.-Family:The Earl was the...
's private observatory at Dun Echt
Dunecht
Dunecht is a slightly linear village on the A944 road in north-east Aberdeenshire in Scotland. It is not to be confused with Echt.Dunecht is located 12 miles west of the city of Aberdeen and is situated by the confluence of the Kinnernie and Bervie burns.Formerly known as Waterton, it was renamed...
, Aberdeenshire
Aberdeenshire (historic)
Aberdeenshire or the County of Aberdeen is a registration county of Scotland. This area is also a lieutenancy area.Until 1975 Aberdeenshire was one of the counties of Scotland, governed by a county council from 1890...
. In 1874, Gill joined the expedition to Mauritius
Mauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...
to observe the transit of Venus
Transit of Venus
A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and Earth, becoming visible against the solar disk. During a transit, Venus can be seen from Earth as a small black disk moving across the face of the Sun...
. Three years later he went to Ascension Island
Ascension Island
Ascension Island is an isolated volcanic island in the equatorial waters of the South Atlantic Ocean, around from the coast of Africa and from the coast of South America, which is roughly midway between the horn of South America and Africa...
to observe a near approach of Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
and to calculate its distance. While carrying out these laborious calculations, he was notified of his appointment to the Cape Observatory, which, over the following 27 years he was to refurbish completely, turning it into a first-rate institution. Gill was a meticulous observer and had a flair for getting the best out of his instruments. His solar parallax observations with a heliometer
Heliometer
Heliometer is an instrument originally designed for measuring the variation of the sun's diameter at different seasons of the year, but applied now to the modern form of the instrument which is capable of much wider use....
and his calculations of distances to the nearer stars, are testimony to his outstanding work. He recruited Robert Innes to the Cape Observatory.
Gill used the parallax
Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines. The term is derived from the Greek παράλλαξις , meaning "alteration"...
of Mars to determine the distance to the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
, and also measured distances to the star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s. He perfected the use of the heliometer. He was Her Majesty's Astronomer at the Cape of Good Hope
Cape of Good Hope
The Cape of Good Hope is a rocky headland on the Atlantic coast of the Cape Peninsula, South Africa.There is a misconception that the Cape of Good Hope is the southern tip of Africa, because it was once believed to be the dividing point between the Atlantic and Indian Oceans. In fact, the...
from 1879 to 1906. He was a pioneer in the use of astrophotography
Astrophotography
Astrophotography is a specialized type of photography that entails recording images of astronomical objects and large areas of the night sky. The first photographs of an astronomical object were taken in the 1840s, but it was not until the late 19th century that advances in technology allowed for...
, making the first photograph of the Great Comet of 1882
Great Comet of 1882
The Great Comet of 1882 formally designated C/1882 R1, 1882 II, and 1882b, was a comet which became very bright in September 1882...
, and one of the early proponents of the Carte du Ciel
Carte du Ciel
The Carte du Ciel and the Astrographic Catalogue were two distinct but connected components of a massive international astronomical project, initiated in the late 19th century, to catalogue and map the positions of millions of stars as faint as 11th or 12th magnitude...
project.
The invention of dry plate
Dry plate
Dry plate, also known as gelatin process, is an improved type of photographic plate. It was invented by Dr. Richard L. Maddox in 1871, and by 1879 it was so well introduced that the first dry plate factory had been established...
photography by Richard Leach Maddox
Richard Leach Maddox
Richard Leach Maddox was an English photographer and physician who invented lightweight gelatin negative plates for photography in 1871.-Early life:Richard Leach Maddox was born at Bath, England, on August 4, 1816....
made Gill realise that the process could be used to create images of the stars and to more easily determine their relative positions and brightness. This led to a massive project in collaboration with the Dutch astronomer J.C. Kapteyn
Jacobus Kapteyn
Jacobus Cornelius Kapteyn, was a Dutch astronomer, best known for his extensive studies of the Milky Way and as the first discoverer of evidence for galactic rotation....
, and the compiling of an index of brightness and position for some half a million southern stars. The work was published as Cape Photographic Durchmusterung in 3 volumes between 1896 and 1900. Gill also played a leading role in the organising of the Carte du Ciel, an ambitious international venture aimed at mapping the entire sky. He initiated the idea of a geodetic survey along the 30th east meridian stretching from South Africa to Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
, resulting in the longest meridian yet measured on Earth.
Gill married in 1870, and his wife accompanied him to Ascension Island for his Mars observations. On Gill's retirement in 1906, the couple moved to London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
, where Gill served for two years (1909–1911) as president of the Royal Astronomical Society
Royal Astronomical Society
The Royal Astronomical Society is a learned society that began as the Astronomical Society of London in 1820 to support astronomical research . It became the Royal Astronomical Society in 1831 on receiving its Royal Charter from William IV...
before his death in 1914. He was buried in Aberdeen.
Selected writings
His writings include memoirs on "Heliometer Determination of Stellar Parallax in the Southern Hemisphere" and "A Determination of the Solar Parallax and Mass of the Moon from Heliometer Observations of Victoria and Sappho" (in Annals of the Cape Observatory, volumes vi and vii, 1896). He also wrote A Determination of the Solar Parallax from Observations of Mars at the Island of Ascension (in the Memoirs of the Royal Astronomical SocietyRoyal Astronomical Society
The Royal Astronomical Society is a learned society that began as the Astronomical Society of London in 1820 to support astronomical research . It became the Royal Astronomical Society in 1831 on receiving its Royal Charter from William IV...
, volumes xlvi and xlviii, 1881 and 1885). New International Encyclopedia
New International Encyclopedia
The New International Encyclopedia was an American encyclopedia first published in 1902 by Dodd, Mead and Company. It descended from the International Cyclopaedia and was updated in 1906, 1914 and 1926.-History:...
In 1913 he published A History and Description of the Royal Observatory at the Cape of Good Hope.
Honours
- Elected Fellow of the Royal Society, 7 June 1883
- Knighted, 24 May 1900
- President, Royal Astronomical SocietyRoyal Astronomical SocietyThe Royal Astronomical Society is a learned society that began as the Astronomical Society of London in 1820 to support astronomical research . It became the Royal Astronomical Society in 1831 on receiving its Royal Charter from William IV...
, 1909–1911 - Member of the Royal Swedish Academy of SciencesRoyal Swedish Academy of SciencesThe Royal Swedish Academy of Sciences or Kungliga Vetenskapsakademien is one of the Royal Academies of Sweden. The Academy is an independent, non-governmental scientific organization which acts to promote the sciences, primarily the natural sciences and mathematics.The Academy was founded on 2...
, 1910
Awards
- Bruce MedalBruce MedalThe Catherine Wolfe Bruce Gold Medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. It is named after Catherine Wolfe Bruce, an American patroness of astronomy, and was first awarded in 1898...
(1900) - Gold Medal of the Royal Astronomical SocietyGold Medal of the Royal Astronomical Society-History:In the early years, more than one medal was often awarded in a year, but by 1833 only one medal was being awarded per year. This caused a problem when Neptune was discovered in 1846, because many felt an award should jointly be made to John Couch Adams and Urbain Le Verrier...
(1882 and 1908) - James Craig Watson MedalJames Craig Watson Medalthumb|right|400px|James Craig Watson MedalThe James Craig Watson Medal was established by the bequest of James Craig Watson, and is awarded by the U.S. National Academy of Sciences for contributions to astronomy.The recipients have been:-External links:*...
(1899)
Named after him
- Gill (lunar crater)Gill (lunar crater)Gill is a lunar crater that is located near the southeastern limb of the Moon. Due to its proximity to the edge of the Moon as seen from the Earth, this crater is viewed nearly from the side and it can become hidden from sight due to libration. The crater lies to the southwest of the irregular Mare...
- Gill (Martian crater)
External links
at the Internet ArchiveInternet Archive
The Internet Archive is a non-profit digital library with the stated mission of "universal access to all knowledge". It offers permanent storage and access to collections of digitized materials, including websites, music, moving images, and nearly 3 million public domain books. The Internet Archive...
- Bruce Medal page
- Awarding of Bruce Medal: PASP 12 (1900) 49
- Awarding of RAS gold medal, 1882: MNRAS 42 (1882) 216
- Awarding of RAS gold medal, 1908: MNRAS 68 (1908) 317
- Biographical sources