[Extracts from the City of Armagh list by Robert McKinstry, Richard Oram, Roger Weatherup and Primrose Wilson; published by the Ulster Architectural Heritage Society in 1992.]
A. (1789-91) Architect Francis Johnston.
From the gate lodge at the bottom of College Hill the drive winds up Knockboy to the Observatory buildings sited at the top. The buildings form an important element in Primate Robinson's overall plan, both as an element of his university project and as a practical ornament in the landscape he was creating, to give the whole city an environment of cultured serenity and good taste. Work began on the construction in 1789; as Cooley had died in 1784 the design was entrusted to the archbishop's new protege, Francis Johnston.
This was to be Primate Robinson's last completed scheme for a public building in Armagh. He secured its perpetuity, as he thought, by the endowment of the lands of Derrywaught and the tithes from the parish of Carlingford and he placed its management with a Board of Governors and Guardians. These arrangements were given the formal approval of the Irish Parliament. To mark the achievement Mossop was commissioned to strike a medal, the inscription on this commemorative piece reads 'The Heavens Declare The Glory of God'.
The orientation of the Observatory buildings is the same as that of the Palace and the Royal School, with the entrance on the north face. The buildings are stone with conglomerate rubble for the main walling and ashlar limestone for the dressings. The proportions are classical, the decoration is minimal; the architectural effect is achieved by the subtle relationships of solid to void. The dominant element of the group is the astronomer's lodging. This building is roughly square on plan, has a double pile structure and is formed of two storeys over a basement. The main elevation is three bay, the entrance is central and approached by a fanned flight of seven stone steps. The doorway is cased by a Tuscan prostyle porch in ashlar limestone with block parapet and projecting cornice mould set over modillion brackets. The frieze is decorated by triglyths separated by unadorned metopes. The only decoration of the architrave is the guttae that give emphasis to the triglyphs above. A pair of doors with small pane glazing above the lock rail and timber panels below close the entrance. The windows are all small pane sliding sashes each with a dressed limestone cill, lintel and stepped dressings to the jambs. Chimneys crown all four gables.
Between the pitches of the roofs is a wide platform that has been used to mount various instruments. There is a block parapet delineated by a projecting string course; a second string course defines the basement. All four corners have stepped fielded quoins. The main feature of the south face is the circular telescope tower which bears the same inscription as the medal. Approximately two thirds of the bulk of the tower projects beyond the body of the building and the observation room at the top creates an attic storey.
The whole feature is capped by a hemispherical, copper-clad dome. The telescope is supported on a central limestone pillar rising through the full height of the tower and braced against the outer wall by the stone treads of the spiral stairway. The final ascent into the observation room is via a straight flight below a copper roof with a semi-circular section that rises out of the main roof and is lit by a single curious roof light.
In the interior the detail is restrained and minimal, the joinery is the main architectural element. The tower naturally introduces curves, however other curves have been purposely created for purely aesthetic reasons. In particular the astronomer's study is beautifully lined with curved bookcases and cabinets. The same form is echoed in the shape of the chimney breast. An amazing proportion of the original doors, windows, encasements and fittings have survived decades of every day use. The recent work to convert the lodging to office use and the need to accommodate computers has been skilfully handled with minimum loss of historic fabric.
Adjoining the east gable there is a single storey wing now connected to the lodging but probably originally designed to be separate. It features the square two-storey sector tower built in 1841; the south face is adorned by the arms of Primate Beresford. The slot, in the adjacent pitched roof (now covered) was to allow readings from the Mural Circle. The range is terminated at its eastern end by a second circular tower built in 1827 to house an Herschel telescope. This second tower is very similar to the main one in both size and shape.
Most of the other buildings on the site are relatively modern and not of any particular architectural merit. However there is one exception, the free standing structure, built in 1885 to protect the new Grubb built Robinson Memorial Telescope. It is formed by cast iron columns of minimal section held erect by iron diagonal tension braces. These elements support an iron ring beam that in turn provides a rail for the wheels that allow the dome to be rotated. The compression members of the dome are a series of cast iron quadrant ribs. The tension element is provided by the weather skin of the dome. The whole assembly is an exceptionally elegant engineering design based on the structural principle of a tent and is very economical in its use of materials...
(The following is an extract from the special introductory
essay on the Architecture of Armagh observatory by John Butler):
At the eastern extremity of the Observatory rises a round tower shorter than, but nevertheless rather reminiscent of, those enigmatic bell towers of medieval Irish monasteries. However, instead of a conical roof, it carries a second copper dome, very similar to the earlier dome on the south side of the residence. The tower was built in 1827 and may possibly also be the work of Francis Johnston who died in Dublin two years later. It belonged to the second main phase of building at the Observatory which followed the appointment of John George Beresford as Archbishop of Armagh.
This second dome, I though it was originally built to house a Herschel reflector, became in1834-35 the home of one of the most original and interesting telescopes that has been built in the British Isles. It was the first telescope to be commissioned from Thomas Grubb, founder of the Dublin Telescope Manufacturing Company, and can justly claim to have been the forerunner of many subsequent reflecting telescopes. It had an aperture of 15 inch and included amongst its several innovative features were an equatorial mounting and a clockwork drive.
To the south of the East Dome, at some distance from the main Observatory building, are two low-lying domes, one of which houses the Robinson Memorial Telescope, built in 1885 by Grubb and the other an 18 inch Calver telescope that was later converted into a Schmidt telescope for celestial photography.
The Robinson Memorial Telescope was widely used by Dreyer, the fourth director, to check his earlier observations of nebulae made with Lord Rosse's great six-foot telescope at Birr. Ultimately these observations were compiled in his famous New General Catalogue of Nebulae and Clusters of Stars, first published in 1888 and still in print to-day. It is the order in which they occur in this catalogue which gives the nebulae their well-known NGC number. This world famous book is probably the most important contribution to astronomy to have come from Armagh Observatory. The Robinson Memorial Telescope, or 'Ten Inch', as it is widely known, was also used more recently (1967), by Dr A.D. Andrews and colleagues in a remarkable observation of a huge flare (explosion) on a star, which was seen simultaneously from Armagh and, with the giant two hundred and fifty foot, radio telescope at Jodrell Bank. This type of work, now largely done by satellites, has provided a fruitful line of research for Armagh astronomers over the past two decades...
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