[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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