Natal Observatory
Encyclopedia
The Natal Observatory was an astronomical observatory in the Colony of Natal
(now the KwaZulu-Natal
province of the Republic of South Africa
) from 1882 to 1911. The most important work carried out there was a study of the motion of the moon
.
, director of the Royal Observatory, Cape of Good Hope, requested the government of Natal to establish an astronomical observatory at Durban
, in anticipation of the transit of Venus
on 4 December that year. Mr Robert T. Pett, third assistant at the Royal Observatory, visited Durban in June that year to expedite matters. A site for the observatory was chosen in the southwest corner of the Natal Botanic Gardens. Gill invited the British astronomer Edmund Neville Nevill
(also known as Edmund Neison) to take up the post of government astronomer
of Natal and director of the observatory, urging him to arrive in time to observe the transit. Nevill landed in Durban on 27 November and despite problems with the available equipment managed to observe the transit successfully.
equatorial refracting telescope
donated by the Natal lawyer and politician Harry Escombe, a 75 mm Troughton & Simms
transit instrument
, a clock by Dent keeping sidereal time
, and some chronometer
s and other minor instruments. A mean time clock by Victor Kullberg was added in 1892 and a 75 mm portable equatorial refractor in 1896. In December 1883 meteorological instruments were received from England and regular meteorological observations initiated at the observatory. Instruments to measure magnetic declination
arrived in 1892.
in 1857) and observations had become so large that navigators could no longer use the moon's position to determine their longitude
accurately. Nevill tackled the problem by first verifying Hansen's treatment of lunar perturbations caused by the direct action of the sun
. He then devised an improved method for calculating perturbations
caused by Venus
. The remaining errors he ascribed to the gravitational pull of the other planets, whose effects were very difficult to calculate. This work was published, among others, in a paper in the Memoirs of the Royal Astronomical Society
(1885), describing the corrections required by Hansen’s tables. He next studied all available lunar observations since the middle of the 17th century and reduced them to a uniform basis. Comparing these observations to Hansen's tables, he used the discrepancies to derive the amplitudes and periods of appropriate correction terms. After all these improvements the tables provided an excellent fit to all lunar observations made since 1650.
The work was ready for publication by the end of 1894, but no funds were available to have it printed. Each year Nevill urged the Natal government in his annual Report of the Government Astronomer to provide funds for publication
, but to no avail. In his report for 1898 he wrote despairingly: The investigations of the errors in the lunar tables have been wrapped up in brown paper, tied up with red tape, and put away on a shelf until such time as a vote can be obtained to publish it… The next year disaster struck when the manuscript was damaged during a rainstorm owing to a leak in the observatory's roof. In subsequent years similar work was done by others, notably E.W. Brown in the United States, M. Radau in France, and P.H. Cowell in Britain, who received the credit. In 1907 Nevill related this sad history in his presidential address to Section A of the South African Association for the Advancement of Science.
of stars based on observations made in the northern and southern hemispheres
. During his early years in Natal, under the name E.N. Neison, he published a popular book entitled Astronomy: a simple introduction to a noble science (London, 1886). He also made a study of ancient eclipse
s, on which he read a paper at the joint meeting of the British
and South African Associations for the Advancement of Science in 1905.
In addition to the regular meteorological
observations made at the observatory the staff was responsible also for analysing and publishing meteorological observations made elsewhere in Natal. Thus by 1900 there were 31 stations that submitted their observations to the observatory on a monthly basis. In 1908 Nevill wrote an article on the rainfall in Natal for the Natal Agricultural Journal, in which he identified an 18 year rainfall cycle. Rendell also published a paper on the rainfall at Durban in the Quarterly Journal of the Royal Meteorological Society
in 1906.
The staff also analysed tidal observations made during 1884-1888 and compiled tidal tables for Durban Harbour. By 1903 these had still not been printed and by that time the entrance to the harbour had changed so much that more recent tidal observations needed to be analysed, for which there were no funds. From 1893 daily observations of the magnetic declination were made at the observatory. In November 1887 Nevill was appointed also as Government Chemist and Official Assayer for Natal, which further reduced the time available for astronomical research. His chemical work was mainly of a routine nature and included analyses of geological samples for gold
and other metal
s, analyses of soil samples for agricultural purposes, the examination of high explosives and detonator
s, and toxicological
investigations.
Colony of Natal
The Colony of Natal was a British colony in south-eastern Africa. It was proclaimed a British colony on May 4, 1843 after the British government had annexed the Boer Republic of Natalia, and on 31 May 1910 combined with three other colonies to form the Union of South Africa, as one of its...
(now the KwaZulu-Natal
KwaZulu-Natal
KwaZulu-Natal is a province of South Africa. Prior to 1994, the territory now known as KwaZulu-Natal was made up of the province of Natal and the homeland of KwaZulu....
province of the Republic of South Africa
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...
) from 1882 to 1911. The most important work carried out there was a study of the motion of the moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
.
Founding of the observatory
In 1882 David GillDavid Gill (astronomer)
Sir David Gill FRS 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.- Life and work :...
, director of the Royal Observatory, Cape of Good Hope, requested the government of Natal to establish an astronomical observatory at Durban
Durban
Durban is the largest city in the South African province of KwaZulu-Natal and the third largest city in South Africa. It forms part of the eThekwini metropolitan municipality. Durban is famous for being the busiest port in South Africa. It is also seen as one of the major centres of tourism...
, in anticipation of 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...
on 4 December that year. Mr Robert T. Pett, third assistant at the Royal Observatory, visited Durban in June that year to expedite matters. A site for the observatory was chosen in the southwest corner of the Natal Botanic Gardens. Gill invited the British astronomer Edmund Neville Nevill
Edmund Neville Nevill
Edmund Neison FRS , whose real name was Edmund Neville Nevill, wrote a key text in selenography called The Moon and the condition and configuration of its surface and later set up an observatory in Durban, Natal Province...
(also known as Edmund Neison) to take up the post of government astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
of Natal and director of the observatory, urging him to arrive in time to observe the transit. Nevill landed in Durban on 27 November and despite problems with the available equipment managed to observe the transit successfully.
Equipment
The Natal Observatory was initially equipped with a 200 mm GrubbSir Howard Grubb, Parsons and Co. Ltd.
Sir Howard Grubb, Parsons and Co. Ltd. was a telescope manufacturer, more commonly known as Grubb Parsons based in Newcastle upon Tyne.-History:...
equatorial refracting telescope
Refracting telescope
A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...
donated by the Natal lawyer and politician Harry Escombe, a 75 mm Troughton & Simms
Troughton & Simms
Troughton & Simms was a British instrument-making firm, formed when Edward Troughton in his old age took on William Simms as a partner in 1826.It became a limited company in 1915 and in 1922 it merged with T...
transit instrument
Transit instrument
In astronomy, transit instruments are used for the precise observation of star positions. The instruments can be divided into three groups:- Meridian instruments :for observation of star transits in the exact direction of South or North:...
, a clock by Dent keeping sidereal time
Sidereal time
Sidereal time is a time-keeping system astronomers use to keep track of the direction to point their telescopes to view a given star in the night sky...
, and some chronometer
Chronometer
Chronometer may refer to:* Chronometer watch, a watch tested and certified to meet certain precision standards* Hydrochronometer, a water clock* Marine chronometer, a timekeeper used for celestial navigation...
s and other minor instruments. A mean time clock by Victor Kullberg was added in 1892 and a 75 mm portable equatorial refractor in 1896. In December 1883 meteorological instruments were received from England and regular meteorological observations initiated at the observatory. Instruments to measure magnetic declination
Magnetic declination
Magnetic declination is the angle between magnetic north and true north. The declination is positive when the magnetic north is east of true north. The term magnetic variation is a synonym, and is more often used in navigation...
arrived in 1892.
Staff
Nevill remained director of the observatory until it was closed in 1911, following the incorporation of Natal into the Union (now the Republic) of South Africa in 1910. He was assisted by, among others, the following persons:- John Grant, human computer from November 1883 to 1885, then astronomical assistant to the end of 1886 when funds for his post ran out. Re-appointed as astronomical assistant from February 1888 to 1890.
- Mabel Grant (South Africa's first women's single tennis champion from 1891 to 1894), human computer from 1887 or earlier to 1890, meteorological assistant to August 1891, and (senior) astronomical assistant from 1 September 1891 to April 1903. She married Nevill in 1894.
- Miss B. Grant, human computer from 1887 or earlier to 1891, then meteorological assistant to September 1894. A number of other ladies did computational work at the observatory, including several further members of the Grant family.
- Frederick A. (Fred) Hammond (born 1853), meteorological assistant from 1 October 1894 to 1909.
- Hugh C. Mason (1873–1936), junior astronomical assistant from 1 December 1897 to June 1900.
- Robert F. Rendell (born 1873), FRAS, formerly of the Royal Greenwich Observatory, senior astronomical assistant from April 1903 to March 1907.
- Arthur E. Hodgson (born 1880), FRAS, formerly of the Solar Physics Observatory at South KensingtonSouth KensingtonSouth Kensington is a district in the Royal Borough of Kensington and Chelsea in London. It is a built-up area located 2.4 miles west south-west of Charing Cross....
, junior astronomical assistant from May 1903 to the end of 1909, and senior astronomical assistant from 1 January 1910 until the observatory closed.
Research on the motion of the moon
During the 1880s the discrepancies between the best available lunar tables (published by HansenPeter Andreas Hansen
Peter Andreas Hansen was a Danish astronomer, was born at Tønder, Schleswig.-Biography:The son of a goldsmith, Hansen learned the trade of a watchmaker at Flensburg, and exercised it at Berlin and Tønder, 1818–1820...
in 1857) and observations had become so large that navigators could no longer use the moon's position to determine their longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
accurately. Nevill tackled the problem by first verifying Hansen's treatment of lunar perturbations caused by the direct action of 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...
. He then devised an improved method for calculating perturbations
Perturbation (astronomy)
Perturbation is a term used in astronomy in connection with descriptions of the complex motion of a massive body which is subject to appreciable gravitational effects from more than one other massive body....
caused by Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
. The remaining errors he ascribed to the gravitational pull of the other planets, whose effects were very difficult to calculate. This work was published, among others, in a paper in the Memoirs 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...
(1885), describing the corrections required by Hansen’s tables. He next studied all available lunar observations since the middle of the 17th century and reduced them to a uniform basis. Comparing these observations to Hansen's tables, he used the discrepancies to derive the amplitudes and periods of appropriate correction terms. After all these improvements the tables provided an excellent fit to all lunar observations made since 1650.
The work was ready for publication by the end of 1894, but no funds were available to have it printed. Each year Nevill urged the Natal government in his annual Report of the Government Astronomer to provide funds for publication
Publication
To publish is to make content available to the public. While specific use of the term may vary among countries, it is usually applied to text, images, or other audio-visual content on any medium, including paper or electronic publishing forms such as websites, e-books, Compact Discs and MP3s...
, but to no avail. In his report for 1898 he wrote despairingly: The investigations of the errors in the lunar tables have been wrapped up in brown paper, tied up with red tape, and put away on a shelf until such time as a vote can be obtained to publish it… The next year disaster struck when the manuscript was damaged during a rainstorm owing to a leak in the observatory's roof. In subsequent years similar work was done by others, notably E.W. Brown in the United States, M. Radau in France, and P.H. Cowell in Britain, who received the credit. In 1907 Nevill related this sad history in his presidential address to Section A of the South African Association for the Advancement of Science.
Other scientific work
Nevill's other astronomical work included the accurate determination of the observatory's latitude and longitude, first for astronomical purposes and then for the geodetic survey of southern Africa, and regular transit observations for the provision of time signals. A larger collaborative project, carried out from 1886 to 1896, involved the comparison of the declinationDeclination
In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...
of stars based on observations made in the northern and southern hemispheres
Celestial sphere
In astronomy and navigation, the celestial sphere is an imaginary sphere of arbitrarily large radius, concentric with the Earth and rotating upon the same axis. All objects in the sky can be thought of as projected upon the celestial sphere. Projected upward from Earth's equator and poles are the...
. During his early years in Natal, under the name E.N. Neison, he published a popular book entitled Astronomy: a simple introduction to a noble science (London, 1886). He also made a study of ancient eclipse
Eclipse
An eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer...
s, on which he read a paper at the joint meeting of the British
British Association for the Advancement of Science
frame|right|"The BA" logoThe British Association for the Advancement of Science or the British Science Association, formerly known as the BA, is a learned society with the object of promoting science, directing general attention to scientific matters, and facilitating interaction between...
and South African Associations for the Advancement of Science in 1905.
In addition to the regular meteorological
Meteorology
Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...
observations made at the observatory the staff was responsible also for analysing and publishing meteorological observations made elsewhere in Natal. Thus by 1900 there were 31 stations that submitted their observations to the observatory on a monthly basis. In 1908 Nevill wrote an article on the rainfall in Natal for the Natal Agricultural Journal, in which he identified an 18 year rainfall cycle. Rendell also published a paper on the rainfall at Durban in the Quarterly Journal of the Royal Meteorological Society
Royal Meteorological Society
The Royal Meteorological Society traces its origins back to 3 April 1850 when the British Meteorological Society was formed as a society the objects of which should be the advancement and extension of meteorological science by determining the laws of climate and of meteorological phenomena in general...
in 1906.
The staff also analysed tidal observations made during 1884-1888 and compiled tidal tables for Durban Harbour. By 1903 these had still not been printed and by that time the entrance to the harbour had changed so much that more recent tidal observations needed to be analysed, for which there were no funds. From 1893 daily observations of the magnetic declination were made at the observatory. In November 1887 Nevill was appointed also as Government Chemist and Official Assayer for Natal, which further reduced the time available for astronomical research. His chemical work was mainly of a routine nature and included analyses of geological samples for gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
and other metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
s, analyses of soil samples for agricultural purposes, the examination of high explosives and detonator
Detonator
A detonator is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the latter two being the most common....
s, and toxicological
Toxicology
Toxicology is a branch of biology, chemistry, and medicine concerned with the study of the adverse effects of chemicals on living organisms...
investigations.