The history of Armagh Observatory is inextricably intertwined with that of the city of Armagh, which has a rich and storied history replete with famous characters and beautiful buildings, as well as with other notable astronomical figures and institutions.

The ‘Read more’ buttons will lead you to selected chapters from ‘A Short History of Armagh Observatory’ by Dr C. J. Butler, adapted to the online format.

The City of Armagh

While the area has been inhabited since the Neolithic period, the city of Armagh probably dates back to the 5th century AD, during which time St Patrick founded his first church there. For the next four centuries Armagh was renowned throughout Europe as an ecclesiastical centre and was regarded as the ‘Metropolis of Ireland’. During this period the religious colleges in Armagh were said to have had several thousand students.

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The Rise of Astronomy in the 18th Century

The Age of Enlightenment saw a steady increase in the study of science. Astronomy at that time found itself at the forefront both with the increased interest in experimentation and observations, and with the increase in maritime trading, for which the science of navigation by celestial objects was turning out to be crucial. Events like Captain Cook’s observations of the transit of Venus in 1769 and the discovery of planet Uranus by Sir William Herschel also helped bring astronomy to greater prominence in the public eye.

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An Observatory for Armagh

Richard Robinson, Lord Archbishop of Armagh, was a rich and influential man who embodied the spirit of his age. As an educated and enlightened man he resolved to use his wealth and power to found and maintain charitable and educational institutions, particularly in Armagh. He employed some of the foremost architects of his day, Thomas Cooley and Francis Johnston, to design buildings and plan his cathedral city. As part of his plans to start a university in the city, he founded the Armagh Observatory on one of the prominent hills. It is the oldest scientific institution in Northern Ireland, and only a few years younger than Dunsink Observatory near Dublin.

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Dr J A Hamilton and the Early Instruments

Dr J. A. Hamilton was closely involved in the conception of the Observatory and may well have made the initial suggestion to Archbishop Robinson. It was natural, therefore, that he should be chosen as its first Director. Despite a relative dearth of funds after Robinson’s early death in 1794, Hamilton successfully started the early observations of stars as well as the meteorological record – efforts which continued to define the work of the Observatory through the centuries and to the present day.

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The Earnshaw Clocks

The measurement and keeping of time was, for centuries, one of the most important functions of an observatory. Thus it was necessary to ensure that observatories possessed the most accurate clocks available. In the 18th century the art of making pendulum clocks improved remarkably and one of the most outstanding clock makers at that time was Thomas Earnshaw of London, who is known as the father of the chronometer.

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Thomas Romney Robinson and the New Instruments

Thomas Romney Robinson, the third director of the Observatory, was, by all accounts, a remarkable man of many interests. In 1823 he was appointed director of Armagh Observatory a post which he retained for a total of 59 years and a world record for an observatory director which still stands today! With the help of a new Archbishop, Primate Beresford – a rich and generous person who took a great deal of interest in science – he was able to obtain a number of new and accurate instruments for the Observatory.

He worked with Thomas Grubb of Dublin on a revolutionary new design for a reflecting equatorial telescope, and was closely involved with the construction and use of the Leviathan of Parsonstown (in what is today Birr, Co. Offaly) – the largest telescope in the world between 1845-1917. He was also heavily involved with the advancement of meteorological readings in the British Isles.

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The Financial Position in the 19th Century

The Observatory, on its foundation in 1790 by Primate Robinson, was endowed with land to provide an income for the Director. This was later supplemented by tithes from an area near Carlingford which would normally have been payable to the Archbishop.

The series of reforms that took place throughout the nineteenth century from Catholic emancipation in 1820 to the Land Acts of the 1890’s had significant repercussions for the pursuit of science in Ireland, and hit the Observatory as well.

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John Louis Emil Dreyer

When Thomas Romney Robinson died on the 28 February 1882 at the age of 89, he was succeeded by John Louis Emil Dreyer, a Dane, who had previously worked at Birr Castle and Dunsink Observatory. Howard Grubb built for him the 10-inch refractor in 1885, situated in the new purpose-built Robinson Memorial Dome, with which he continued his work on observations of nebulae.

Dreyer’s NGC catalogue, or “New General Catalogue of Nebulae and Clusters of Stars” to give it its full name, is probably the single most important contribution to science to have come from Armagh Observatory. Even though it was compiled over 100 years ago it remains to this day the principal catalogue of nebulae and galaxies used by astronomers around the world.

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The decline of scientific research in the early 20th century in Ireland

Scientific research in the eighteenth and nineteenth centuries had, in general, been a pursuit of the rich and well educated Anglo-Irish landowners. Consequently, when the economic power of the landlords was finally broken by the various land reform bills of the late nineteenth and early twentieth centuries, they were no longer able to support and indulge in scientific activity. The decline in income inevitably led to a drop in scientific activity.

Dunsink Observatory, the only other Irish Observatory at that time, entered a period of inactivity as funds from its parent institution, Trinity College Dublin, dried up. Armagh Observatory continued in its work through the efforts of F.A. Ellison. He superseded J.A. Hardcastle, whose poor health and early death prevented him from taking up his position of Director in 1918.

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The Rebirth of Irish Astronomy

Throughout the nineteenth century repeated appeals to the Government for direct and regular assistance to Armagh Observatory were refused. Only sporadic – though sometimes generous – lump-sum payments were made, with no continuing commitment. The mould was finally broken in 1927, when the newly constituted Government of Northern Ireland at Stormont recognised the important work of the Observatory and secured some funding for it.

In 1937 Eric Lindsay – a local man, but educated in Dublin, Belfast, and at Harvard – became the Director of the Observatory. Through his political and scientific prowess, the Armagh-Dunsink-Harvard Telescope was built in South Africa, and a Planetarium erected in Armagh – the first in Ireland.

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Professor Ernst Julius Öpik

EJ Öpik, one of the most outstanding astrophysicists of his generation, came to Armagh Observatory in 1948 as a refugee from Eastern Europe. He had for a while been head of the Astronomy Department at the University of Tashkent, Astronomer at the Tartu Observatory, Estonia and later Rector of the Baltic University, Hamburg.

He worked in a number of fields, from Small Bodies of the Solar System (asteroids, comets, meteors) – among other things, he postulated the existence of the Öpik-Oort cloud as the origin of comets – to stellar structure and evolution.

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Southern Hemisphere Astronomy

Today there are a number of new observatories with large telescopes in remote desert regions of the world where sky conditions are best suited to astronomy. These include the Hawaian Islands, the Canary Islands, Chile, Northern China, South Africa and Australia.

The heavy concentration of telescopes in the first half of this century in the northern hemisphere had led to a striking imbalance in observational astronomy. Several of the most interesting astronomical objects – such as the Large and Small Magellanic clouds, the nearest galaxies to our own – can only be seen from the southern hemisphere. This was one of the main reason Director Eric Lindsay chose South Africa for the location of the Armagh-Dunsink-Harvard telescope.

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Armagh Observatory in the Space Age

For the first 150 years of the Observatory’s existence it relied primarily on observations carried out in Ireland. Since 1950, with the advent of cheap air travel, it has become possible for Armagh astronomers to make observations of high accuracy with telescopes at moderately high altitudes, in dry semi-tropical regions of the world. This trend has continued even more strongly with the advent of the Internet and thus increased connectivity and ease of information transfer between different parts of the world.

During the 1970’s and the 80’s a number of earth satellites have been launched which are designed specifically to make astronomical observations from above the earth’s atmosphere. Astronomers at Armagh Observatory have been making such observations since 1979.

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Current Research Programmes at Armagh Observatory

Throughout the nineteenth century the work at Armagh was primarily concerned with the measurement and cataloguing of the positions of stars, nebulae and galaxies. As our understanding of the physical nature of matter has progressed in this century the emphasis has shifted from positional astronomy to astrophysics.

In astrophysics, we attempt to relate the composition and structure of stars and galaxies to the basic physical processes we can study, theoretically and experimentally, on Earth. An example is the application of our knowledge of nuclear physics and the transmutation of elements, (e.g. H → He), to the structure of the Sun and stars. Sometimes, however, the procedure is reversed and we discover a basic law of physics by attempting to interpret astronomical observations. Such an example would be our understanding of the very dense matter which exists in white dwarfs, neutron stars and black holes; states of matter which do not exist on Earth.

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