An Observatory for Armagh

Richard Robinson, Archbishop of Armagh, was a rich and influential man who embodied the spirit of his age. He was the leader of the established church, the Church of Ireland, and as such received tithes from landowners. He was, however, independently wealthy and by modern standards he would have been a multi-millionaire.

As an educated and enlightened man he resolved to use his wealth and power to found and maintain charitable and educational institutions, particularly in his Primatial City of Armagh. He employed some of the foremost architects of his day: Thomas Cooley, and Francis Johnston, to design buildings and plan his cathedral city.

It is believed that Archbishop Robinson may have been influenced to found an observatory in Armagh by the Reverend J.A. Hamilton, who was to become its first Director. Hamilton, at that time, was Rector of Cookstown, Co. Tyrone, where he had a small private observatory. In 1782 he observed a transit of Mercury and communicated his observations to Maskelyne, the Astronomer Royal for England who presented them to the Royal Society of London. It is reported that Archbishop Robinson was so impressed with Hamilton’s observations that he decided to include an Observatory in his plans for Armagh City.

The Observatory, like several of the Archbishop’s foundations, was built on a hill so that it could be seen against a natural woodland setting from his new palace. It was designed by Francis Johnston, the city architect, who was responsible for several fine buildings in Dublin; notably, the Chapel Royal and the GPO in O’Connell Street. The new observatory was the second to be established in Ireland; (the first was Dunsink Observatory near Dublin). It is the oldest scientific institution in Northern Ireland.

In some 17th C observatories, notably Paris (1667), the architectural elegance of the structure was considered more important than its practicality for astronomy This was true to a lesser extent in Wren’s design for the Royal Observatory (1675) at Greenwich where, in spite of its grand facade, the structure did not actually impede observations. Normally, at that time, observations were made from either an outside platform or alternatively from inside a large room with tall windows. The instruments were usually portable, with a mounting which simply rested upon a table or the floor and therefore were easily shaken by the movement of people across the room. As instruments increased in size during the 18th and 19th centuries they required more substantial support to avoid vibration.

The buildings of Dunsink (1785) and Armagh (1790) Observatories represent a revolution in observatory design. At Dunsink and Armagh, for the first time, the requirements for the stability of the instruments took priority over aesthetic considerations. Unlike the dome of the King’s Observatory, Kew (1768), which is insubstantial and appears almost as an afterthought, the domes at Dunsink and Armagh dominate the structure and form the central theme of the building. In addition the stability of the instruments was guaranteed by placing them on substantial stone pillars brought up from the substrata below the building. At Dunsink these pillars were free standing and not joined to the rest of the building. In this way, any vibrations originating in the main part of the structure, were not transmitted to the instruments. These principles of construction have been employed in most subsequent observatory buildings throughout the world.

Both Dunsink and Armagh Observatories have only sparse ornamentation on their exteriors which is very much in keeping with the new scientific practicality they represented. However, the ornamentation on the exterior at Armagh, restrained as it is, is continued around the building on all sides, quite unlike many 18th C Irish buildings which had a single ornamental facade.

The interior design of Armagh Observatory has a number of unusual features – such as the frequent use of circular motifs; e.g. curved corners to the rooms and bowed chimney breasts. It has one of the best preserved 18th C interiors in N. Ireland.

From the inception of the Archbishop’s plan to found an Observatory in Armagh the Reverend J.A. Hamilton, who was to be the first Director, was in touch with one of the leading astronomers of his day, Neville Maskelyne, the Astronomer Royal for England. Maskelyne wrote a letter detailing the requirements for a modern observatory and offered to vet and purchase equipment in London for the Primate’s new Observatory.

The principal requirements for serious work on the position of stars were: a transit instrument, a meridian circle and an accurate clock. Whilst Maskelyne successfully obtained for Armagh two of the finest astronomical clocks available, the two masterpieces by Thomas Earnshaw, he was not so successful with the other instruments.

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