2. Armagh Observatory: the early years

Mossop Medal
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Fig.4 Bronze medallion by George Mossop of Dublin, 1789 with the inscription The heavens declare the glory of God.

Construction of the Armagh Observatory began in 1789 when Archbishop Robinson was eighty years of age. To mark the occasion, a medallion was struck by the great Irish medallist George Mossop. The obverse side shows a relief profile of Archbishop Robinson and the south elevation of the Observatory is on the reverse side.

1791 Act of Parliament
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Fig.5 The Act of the Irish Parliament (Grattan's) establishing the Armagh Observatory, 1791.

For the site of his Observatory, Robinson chose the summit of Knockboy hill within the city limits to the northeast of Armagh. The architect was Francis Johnston, who was born at Kilmore, County Armagh, an apprentice and the successor, of Thomas Cooley. Johnston created a fairly plain classical Georgian mansion. Several false windows provide the necessary symmetry. The late Sir John Betjeman (Poet Laureate 1972 - 1984) had a high regard for Johnston's work claiming that he was the first man to be famous as an Irishman and an architect. The building is principally faced with a conglomerate sandstone with limestone trimmings. A fanned Armagh marble stairway leads up to the entrance door on the north facade. The south elevation has a prominent circular telescope tower bearing the date 1793 in Roman numerals.

The Observatory was established by an Act of the Irish Parliament in 1791 following the appointment of Revd. Dr James Archibald Hamilton as the first Astronomer in July 1790. The Archbishop also donated 20 acres of the surrounding land to the Observatory in addition to the rent and tithes from estates at Tullynure and Derrynaught and the parish of Carlingford.

Troughton Equatorial Telescope
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Fig.6 Troughton equatorial telescope, 1795

The new observatory was equipped with a state-of-the-art telescope and astronomical clocks procured through the offices of the Astronomer Royal, Nevil Maskelyne, at the request of Archbishop Robinson. The equatorial telescope was furnished in 1795 by the London firm of John and Edward Troughton, and the dome is now believed to be the oldest in the world with its original telescope still in situ. Thomas Earnshaw supplied two outstanding astronomical clocks.

The equatorial telescope was used for general observations and to measure the declinations of a set of standard stars. The correction of observations made with equatorial instruments was the subject of a study by T. R. Robinson. The instrument was also employed by R. Finlay in the rocket experiments to determine the longitude difference between Armagh and Dublin in 1838.

Edward Troughton
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Fig.7 Edward Troughton (1753 - 1835)
(University of St. Andrews, Scotland).

The highly innovative Edward Troughton was probably the greatest English scientific instrument maker of his generation. Born in Cumberland, Edward and his brother John managed their business together until John died. From 1826 until 1835, Edward worked in partnership with William Simms. The Armagh equatorial telescope was a universal instrument of a type which no astronomer had ever seen before.

Thomas Earnshaw
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Fig.8 Thomas Earnshaw
(National Maritime Museum, Greenwich).

Thomas Earnshaw was born in Aston under-Lyme, Lancashire in 1749 and died in London in 1829. He was the first to employ special techniques for the production of chronometers, especially marine chronometers. Earnshaw invented the spring detent escapement and won £3,000 from the Board of Longitude for his contribution towards the solution of the longitude at sea problem.

Earnshaw's first ever long-case clock, is described by him in his "Appeal to the Public" in 1808, where he states his claim to a national reward for his contribution towards the solution of the determination of longitude problem.

Transit Clock by Earnshaw
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Fig.9 The transit clock by Thomas Earnshaw.

In manufacturing the clock, Earnshaw employed devices used in watch making, among which were the use of high numbers, of small teeth, a large amount of jewelling, and a small angle of escape, 0.5 degrees in the (Graham) escapement. On the advice of the Astronomer Royal, Revd. N. Maskelyne, he made the case as nearly air-tight as possible. The clock originally had a nine-bar gridiron pendulum of alternate steel and brass rods which was replaced in 1830 by a mercury pendulum made by Mr Sharp, Sen., of Dublin. Compensating barometers were added to the pendulum in 1832 to endeavour to correct for the effects of varying atmospheric pressure. These barometers were removed in 1835.

Thomas Romney Robinson
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Fig.10 Thomas Romney Robinson
(Royal Irish Academy).

Dr Thomas Romney Robinson became the Astronomer in 1823. The precocious Robinson was able to finance his education at Trinity College Dublin from the contributions of a large number of subscribers to his book: Juvenile Poems, composed before his thirteenth birthday. While at Trinity College he developed an interest in meteorology and in later years invented the cup-anemometer, the wind gauge which now bears his name.

Cup Anemometer
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Fig.11 Robinson Cup-anemometer
(John Butler).

Dr Robinson published a star catalogue in 1859, in which he listed the positions of almost five and a half thousand stars. Robinson prevented the local railway from coming within about 700 metres of the Observatory in order to lessen the vibration of the telescopes. The trains were also restricted to a top speed of 5 mph as they approached Armagh. Robinson remained the director of the Observatory until his death in 1882.

The juvenile T.R. Robinson
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Fig.12 The juvenile T.R. Robinson.

Juvenile Poems of Thomas Romney Robinson, to which is prefixed a short account of the author. It is a collection of twenty-nine poems all written by Robinson before the age of thirteen and printed by J. Smith and D. Lyons of Belfast in 1806. A highly sensitive child, Romney, when about 2 years old, used to listen to his father, Thomas, recite Thomas Percy's ballad, The Hermit of Warkworth, and was reduced to tears on seeing his father's expression at certain passages from the poem.

 List of Subscribers
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Fig.13 Portion of the list of subscribers to T.R. Robinson's Juvenile Poems.

For the full list of subscribers click on the image to the left.

T.R. Robinson Poem
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Fig.14 A poem addressed to W. Ritchie, Belfast: The Triumph of Commerce.

An extract from this poem, written by Robinson when eight years of age, reads:

Now, by thy care, I visit every clime,
While o'er the deep my vessels fly sublime,
Such be thy boast, O Ritchie!....thus proceed,
And through the paths of life let virtue lead; 
With every effort of thy useful art,
With every passion of the feeling heart,
Go, claim the crown excelling virtue brings,
A prize more precious than the wealth of kings:

The full collection of poems may be viewed by clicking on the image to the left. The above poem begins at this page at that location.

The Laganside commercial development in Belfast houses the Clarendon Dock where the shipbuilder William Ritchie built the first ships in the city during the 1790s.

Meteorological Records
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Fig. 15 Meteorological records, Armagh Observatory August 1846

Armagh Observatory has one of the longest meteorological series in the UK and Ireland. It commenced in late 1794 and obviously covers significant periods in our national history such as the Franco-British wars and the Irish famine period. This database can be accessed online at the climate web site and has been analysed in relation to climate change studies. One prominent result emerging from these studies is the link between the Sun's activity as measured by the length of the sunspot cycle and our mean air temperatures - the shorter the cycle, the higher the mean air temperatures in our essentially maritime, mid-latitude climate.

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Fig.16 Title page of the New General Catalogue of Nebulae and Clusters of Stars, 1888.

Robinson's successor was a competent young Danish astronomer, Dr J.L.E. Dreyer. Born in Copenhagen in 1852, Dreyer came to work first at the Earl of Rosse's observatory in Parsonstown, King's County (Birr, Co. Offaly) and then to Dunsink Observatory near Dublin before being appointed to Armagh in 1882. Nowadays he is best remembered as an historian of science and compiler of the New General Catalogue of Nebulae and Clusters of Stars. Most bright galaxies and star clusters have NGC numbers and astronomers across the world still refer to Dreyer's great work. In 1890 he published a biography of that other early Danish astronomer, Tycho Brahe, to be followed many years later by his monumental collected works of Tycho.

JLE Dreyer
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Fig. 17 Johann Louis Emil Dreyer (1852-1926).

Click on image for short biography.

Joseph Hardcastle Fig. 18 Joseph Alfred Hardcastle.

Following the resignation of Dr Dreyer in 1916, Joseph Alfred Hardcastle was appointed Director. Hardcastle was a great-grandson of Sir William Herschel, the father of sidereal astronomy and discoverer of the planet Uranus in 1781. Hardcastle had undertaken the calculation of the tides for the troops which landed at Gallipoli during World War I. Tragically, Hardcastle died en route to Armagh in November 1917. However, his wife and family did take up residence in the Observatory and remained until October 1918. Mrs Hardcastle carried out meteorological checks for Professor Herbert Hall Turner of the University of Oxford.

Mrs Hardcastle etc Fig. 19 Mrs T.C. Hardcastle, Félicité F. and M.H. Hardcastle.
Hardcastle Letter Fig. 20 From the Hardcastle family scrapbook: Extracts from two letters written in 1782 and 1784 by J. de la Lande to W. Herschel relating to the symbol adopted for the planet Uranus.
WFA Ellison Fig. 21 William Frederick Archdall Ellison (1864 - 1936).

Revd William F.A. Ellison's directorship covered the period 1918 to 1936. Widely respected as a competent telescope maker, he wrote several books and articles on the subject. He wrote a substantial contribution to the Amateur Telescope Making series. Ellison was a highly regarded planetary observer, in particular of Mars, and visual double star observer. According to Patrick Moore, he appears to have been one of the few people to have observed an eclipse of Saturn's satellite Iapetus by the shadow of Saturn's outer, A, ring on 28 February 1918.

The Amateur's Telescope Fig. 22 The Amateur's Telescope by W.F.A. Ellison, 1920.

Last Revised: 2011 May 13th