Armagh Observatory, College Hill, Armagh,
Northern Ireland BT61 9DG, U.K.
Armagh Observatory and Museum was founded in 1789 by Richard Robinson (1708 - 1794), Lord Archbishop of Armagh and Primate of All Ireland (1765 - 1794). Primate Robinson also founded and endowed other establishments in Armagh such as the Public Library in 1771. The building of an Observatory in Armagh may have been to the Primate a step towards the formation of a University in Ulster, as he had been interested in such an institute (Dreyer 1883a). However, the University did not materialise at that time.
The first Astronomer of the Observatory, Revd. Dr. J. A. Hamilton, was appointed in July 1790, and as an endowment for the Astronomer, Primate Robinson gave twenty acres of land and the estate of Derrynaught. Several instruments, including a Ramsden transit instrument and meridian circle, a Troughton equatorial telescope and three clocks, were ordered at the Primate's expense. However, owing to the Primate's death before receipt of all the instruments, the two Ramsden instruments never came to Armagh (Robinson 1829, p.i). The Troughton equatorial and the three clocks (including Thomas Earnshaw's first two) did arrive. One of these clocks has been described as unusually good (Dreyer 1883b). The then Astronomer Royal, Revd. N. Maskelyne, advised that the clock case should be made as air-tight as possible. Earnshaw, being somewhat apprehensive about constructing a clock (he was a chronometer maker), made his now famous quotation in reply to Maskelyne's request for a clock for Primate Robinson: "I told him [Maskelyne] I had never made a clock, and did not know how many wheels were in one; and asked him, if I were to make one, how near he expected it to go. He [Maskelyne] said, he should not allow more than half a second per day error; I replied, that if the great clock makers, Graham, Harrison, Shelton, Kendal and Arnold, could not make a clock go to half a second per day, what hope had he that I could do it who had never yet made one". However, Earnshaw took Maskelyne's advice and constructed the clock. It was sent for trial to the Royal Observatory in February 1792 (Earnshaw 1808).
The Troughton equatorial, with an aperture of 2.5 inches, was erected in 1795. With it, the declinations of thirty seven standard stars were measured and the results published in the Philosophical Transactions of the Royal Society (Pond 1806).
Compensating for the non-arrival of the Ramsden transit instrument, an Armagh watchmaker, Mr James Waugh, constructed one, and observations with it commenced in July 1793 (Stuart 1819). Some results with this instrument were published in the Transactions of the Royal Irish Academy (Hamilton 1810).
During the season 1794-95, Hamilton employed a 42-inch Dollond refractor to make observations of the Sun's apparent diameter in order to test the relative accuracy of a wire- micrometer and an object-glass micrometer, both by Dollond, with a 10-inch sextant by Troughton (Hamilton 1806).
Dr Hamilton held office until 1815, when he was succeeded by Revd. Dr. W. Davenport. During Davenport's occupation, his assistant, Revd. R. Hogg, continued to use the locally-made transit instrument. Davenport died in 1823 and he in turn was succeeded by Revd. Dr. J. T. R. Robinson, who held office until 1882.
At the commencement of Robinson's term, the Observatory's instrumentation was virtually the same as in 1795. Since there were severe limitations in the use to which the Troughton equatorial and the transit instrument could be put, the then Primate, Lord John George Beresford, ordered a new transit instrument and a mural circle from Thomas Jones of London. The transit instrument was erected in 1827 and the mural circle arrived in 1831. After some improvements were made to the mural circle, and with the aid of an electric chronograph, Robinson commenced measuring the places of certain stars selected from those observed by Lalande (Robinson 1879, Dreyer 1886). With these instruments, Robinson carried out the observations which lead to the publication of the catalogue: "Places of 5,345 Stars observed from 1828 to 1854 at the Armagh Observatorv" (Robinson 1859). In this work, Robinson gives details of the instruments.
A Herschel reflector of ten feet focal length which had been housed under the East dome was replaced by a Grubb reflector of 15 inches aperture in 1835. This equatorially mounted reflector had a clock movement and the first ever three-point floating suspension speculum mirror cell (Grubb 1932). The mounting was constructed as an experimental model of Cooper's equatorial, calculated to bear a 10-foot Newtonian of Sir William Herschel, but was capable of carrying the 15-inch reflector (Robinson 1842).
In 1841, Armagh Observatory was honoured by the gracious presentation by Her Majesty Queen Victoria of part of the King George III Collection of Scientific Instruments, formerly housed at the King's private Observatory at Kew, Surrey. The items sent, and the scenario relating to their journey to Armagh were described by Dr. E. M. Lindsay, a former Director of Armagh Observatory (Lindsay 1969), and include four refracting telescopes, two reflecting telescopes, a Herschel mirror, six clocks, a transit instrument, a brass quadrant, a telescope stand, an equatorial sector, an equal altitude instrument, and a zenith sector.
Following the death of Robinson, Dr. J. L. E. Dreyer, a Dane, assumed the directorship. Dreyer initiated a memorial fund for the purchase of a refracting telescope in memory of Dr. Robinson. This fund reached the sum of 100 pounds and, together with a contribution of 2000 pounds from the Treasury, it became possible to order a refractor of 10 inches aperture from Howard Grubb of Dublin, and have a dome for it constructed. The 10- inch refractor came into operation in 1885 and was used by Dreyer to examine certain nebulae suspected of change (Dreyer 1887, 1891). Also, some objects of uncertain nature were examined during the compilation of "A New General Catalogue of Nebulae and Clusters of Stars" (Dreyer 1888), the catalogue prepared by Dreyer at the suggestion of the Royal Astronomical Society, and which is still universally referred to. Between the years 1888 and 1893, the refractor was used to make micrometer measures of nebulae and adjacent stars (Dreyer 1894). From 1893, observations of double stars, and investigations of systematic errors in transit observations were made (Dreyer 1896a,b).
A Troughton and Simms micrometer-microscope was purchased by a grant from the Royal Society and arrived at the Observatory in 1899 (Dreyer 1910). With this instrument, Dreyer carried out a survey of the stars and nebulae in the galaxy Messier 33, utilizing photographic plates exposed by Isaac Roberts (Dreyer 1904).
In 1919, the then Director, Revd. W. F. A. Ellison, presented an 18-inch Calver reflector to the Observatory. Ellison had acquired this instrument from John Pierce of the Wexford Engineering Works. Studies of stellar spectra were carried out with this reflector. With a grant from the Royal Society, the optical parts of this instrument were converted into a 12"/18" Schmidt camera in 1950 by the firm of Cox, Hargreaves and Thomson, who also provided an electronic synchronised drive. The mounting of the Calver reflector was retained.
Ellison completed a 6-inch refractor in 1921 and mounted it on the equatorial of the 15" Grubb reflector in the East dome. This refractor also employed the clock drive of the 15-inch Grubb reflector.
Under an international agreement involving Armagh, Dunsink and Harvard Observatories, a large southern hemisphere Baker- Schmidt telescope manufactured by Perkin-Elmer came into operation in 1950. The instrument was designed by Professor James Baker of Harvard University and became known as the ADH telescope. The world's then largest objective prism of 33 inches diameter was provided for the telescope through funds from Harvard and The Queen's University of Belfast. The ADH telescope (32"/35.6", f/3.75) was mounted on the Fecker mounting of the 24" Bruce telescope situated at the Boyden station of the Harvard Observatory in Bloemfontein, South Africa. Photographs exposed with this instrument have been used in the study of globular clusters, cluster Cepheids, and the nearby galaxies, the Magellanic Clouds.
In the catalogue we have listed the instruments in approximate chronological order of the date of manufacture. Section A contains the instruments still at the Observatory; Section B contains a list of the instruments no longer at the Observatory for one reason or another, that is, sold, lost or on loan; and Section C contains a listing of instruments not positively identified at present. We have given a brief description of each instrument with maker's name, date and serial number, wherever possible. The King George III Collection of Scientific Instruments has, however, been given fully in Section A (IA1.1-.19) even though several items have been sold or are on loan. M numbers refer to the archives of Armagh Observatory as published by Butler and Hoskin (1987). An asterisk beside the catalogue number means that there is an illustration of the item.
This catalogue has been compiled from various Observatory reports, published articles, and manuscripts. Without the dedication and faithful recording of many people throughout the Observatory's history, this catalogue could not have been collated. The Armagh Observatory is financed by the Department of Education for Northern Ireland. I wish to express my gratitude to the Department for the opportunity to carry out this work.
Butler, J. & Hoskin, M. 1987. "The Archives of Armagh Observatory", Journal for the History of Astronomy, 18, 295. Dreyer, J.L.E. 1883a. "An Historical Account of the Armagh Observatory", p.3. 1883b. ibid., p.6. Dreyer, J.L.E. 1886. Second Armagh Catalogue of 3,300 Stars for the Epoch 1875, deduced from observations made at the Armagh Observatory during the years 1859 to 1883, under the direction of the late T.R. Robinson, DD, FRS, and prepared for publication by his successor, J.L.E. Dreyer, PhD, FRAS, Dublin, xv, 159pp. 1887. "On some nebulae suspected of variability or proper motion", Mon. Not. Roy. astr. Soc., 47, 412; "Note on some apparently variable nebulae", ibid. 52, 100. 1888. "A New General Catalogue of Nebulae and Clusters of Stars", Mem. Roy. astr. Soc., 49, p.1 (See also "Index Catalogue of Nebulae"). ibid., 51, p.185 and "Second Index Catalogue of Nebulae and Clusters of Stars", ibid., 59,p.105). 1891. "Note on some apparently variable nebulae", Mon. Not. Roy. astr. Soc., 52,100. 1894. Trans. Roy. Irish Acad., 30, pt.13. 1896a. Mon. Not. Roy. astr. Soc., 57, 44. 1896b. Report of the Astronomer of the Armagh Observatory for the years 1883 to 1896, p.5. 1904. Proc. Roy. Irish Acad., 25A, 3. 1910. Report of the Astronomer of the Armagh Observatory for the years 1897 to 1910, p.3. Earnshaw, T. 1808. "An Appeal to the Public", London. Grubb, H. 1932. Obituary Notice: Proc. Roy. Soc., Ser.A, 135, No.A828, p.iv. Hamilton, J.A. 1806. Trans. Roy. Irish Acad., 10, 109-117. 1810. ibid. 11, 25-44. Lindsay, E.M. 1969. Irish Astron. Journ., 9, 57. Pond, J. 1806. Phil. Trans. Roy. Soc., 453-454. Robinson, T.R. 1829. "Astronomical Observations made at the Armagh Observatory", Vol.I, Pt.I. 1830. "Astronomical Observations made at the Armagh Observatory", Vol.I, Pt.II. 1835. Mem. Roy. astr. Soc., 9, 17. 1842. Report made at the Annual Visitation of the Armagh Observatory, p.5. 1859, "Places of 5,345 Stars observed from 1828 to 1854 at the Armagh Observatory", Dublin. 1879. "Places of one thousand Stars observed at the Armagh Observatory",Trans. Roy. Dublin Soc., 1, Ser.2, 101. Stuart, J. 1819. "Historical Memoirs of the City of Armagh", 523-527.
IA1 His Majesty King George III Collection of Scientific Instruments presented to Armagh Observatory by Her Majesty Queen Victoria: .1 8-foot Achromatic Telescope by Peter Dollond of the mural circle by Sisson. At the request of Dr Whipple of the Kew Observatory Committee this telescope was returned to Kew by Dreyer in 1889 - the mural circle was in the Science and Art Department of Kew Observatory and the telescope completed the instrument. It is believed to have been recently moved to the Science Museum, London. .2 Small Journeyman Clock by Shelton. On the advice of Professor H H Turner, Savilian Professor of Astronomy at Oxford, this clock and items IA.3,.4,.5 were sold for 25 pounds to Mr W A F Wetherfield in 1918. Wetherfield's collection was sold in 1928 and the two Shelton journeyman clocks probably went to the USA. .3 Large Journeyman Clock by Shelton. Sold to Mr Wetherfield in 1918. .4 Journeyman Clock by Graham. Sold to Mr Wetherfield in 1918. .5 Small Clock by Vulliamy. Sold to Mr Wetherfield in 1918. .6* Transit Instrument by Adams with its reversing apparatus and observing chair. The Adams transit, minus its object glass, reversing apparatus and observing chair, was loaned to Queen's, Belfast c.1851 - no trace can now be found of the Adams transit. .7 Large Astronomical Night Glass - a small short-focus telescope for use at night. Loaned to Queen's, Belfast c.1851. No trace can now be found of it. .8* Astronomical Clock by Recordon. c.1762. .9* 3.9-inch Achromatic Telescope on stand in case. Loaned to Queen's, Belfast c.1851, returned to Observatory minus its object glass and eyepieces. .10* Mean Time Astronomical Clock by Shelton. Used by His Majesty King George III to obtain the exact time of the transit of Venus in 1769. .11* 6-inch Reflector by Thomas Short, London. 1745. 2/1371 = 24, 2 feet focal length. Includes 5 eyepieces, 1 slide filter, and angled mirrors. Used by His Majesty King George III to observe the 1769 transit of Venus. This telescope could be adapted to Newtonian, Cassegrain and Gregorian systems. M92.2 contains an old page of instructions for using the telescope, possibly by Short. .12* 2-foot Gregorian Reflector. .13* Brass Quadrant by J. Sisson, London. 20-inches radius. Has diagonal divisions, a telescope and a plumb-line. .14* Herschel Newtonian Mirror. 9-inches aperture, 10-feet focal length. Reputed to have been made with peculiar care for His Majesty King George III. .15* 8-foot Achromatic Telescope by Peter Dollond? with eyepiece, but no objective. .16* Trial Telescope Stand. .17 Equatorial Sector by Adams. .18* Equal Altitude Instrument by Sisson. .19 Zenith Sector by Sisson. 4.25 inch objective by Peter Dollond, 12-feet focal length. IA2* Brass Astrolabe (Ring dial) IA3* Astronomical Clock by Mudge and Dutton, c.1785. This is the so-called Buchanan clock. This clock had been placed in the West dome of the Observatory. Loaned to the Dean and Chapter of the Church of Ireland Cathedral, Armagh. A clock by J. Crosthwaite was substituted for the Mudge and Dutton clock. (Observatory Minute Book 3/9/1844, p.38). IA4* Astronomical Clock by J. Crosthwaite, Dublin. c.1780s. The clock was constructed for Dr Ussher of Dunsink Observatory. On Ussher's death it was purchased for Armagh Observatory for 40 guineas. The clock has rubied pallets, an eight-day movement, and rated at mean solar time. This clock was attached to a stone pillar in the passage to the transit room. (see Earnshaw's Astronomical Timepieces, M129) IA5* Refractor by John Dollond. 42-inches focal length. This refractor was used by Dr. J. A. Hamilton to make a series of measures of the Sun's apparent diameter in 1794-95, in order to test the relative accuracy of a wire-micrometer and an object-glass micrometer (both by Dollond). See Trans. Roy. Irish Acad., 10, 109-117. IA6 Astronomical Clocks by Thomas Earnshaw. c.1792. .1* The transit clock, 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. In manufacturing the clock, Earnshaw employed devices used in chronometer making, among which were the use of high numbers, small teeth, large amount of jewelling, and a small angle of escape, 0.5 degrees in the (Graham) escapement. On the advice of the then Astronomer Royal, Revd. N. Maskelyne, he made the case as nearly air-tight as possible. The clock originally had a 9- bar gridiron pendulum of alternate steel and brass rods which was replaced in 1830 by a mercurial 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. Extracts from M129: "The clock has an 8-day movement, with finely jewelled pallets and pivot holes. The winding is effected through a valve in the glass front, which when its index points downwards is closed air- tight; when the key with a bit of buff leather on its shank is put into the winding hole, and a compressing spring from the case brought to bear on it by turning the index of the valve up; the key will run in on the axis of the barrel, when the clock is wound, the key is only to be withdrawn till a circular scribe on the shank becomes visible - then the index of the valve is to be brought back to its downward position, before the key is to be intirely removed. The case is made extremely strong and with great care and attention to make it as airtight as possible - which is effected by laying all the necessary opens with waxed cloth, and screwing all home by a great many screws with milled heads". A6.2* Earnshaw's second clock has a 5-bar compensation pendulum of steel and zinc, an 8-day movement, rated at very nearly sidereal time. Its pallets and some of the pivot holes are jewelled. IA7* Theodolite by Dollond. In case. IA8 Object-glass Micrometer by Dollond? c. 1790s. 2-inch aperture. IA9* Equatorial Telescope by E. Troughton. c. 1795. 2.75-inch aperture, 3-feet focal length. The Troughton equatorial arrived in December 1795 and was mounted, in the English style, under the south dome on two stone piers resting on a massive pillar, round which the staircase of the dwelling house winds. There is no polar axis, but the right ascension circle, 4 feet in diameter, is attached to the polar pivots by four stays. The declination circle is of the same size and is similarly attached by stays to two pivots, which turn in Y's fastened to the right ascension circle. A description of the instrument appears in Dr. Rees's Cyclopaedia, The equatorial was used for general observations and to measure the declinations of standard stars (see J. Pond, Phil. Trans. Roy. Soc., 453-454, 1806). The correction of observations made with equatorial instruments was the subject of a study by T. R. Robinson the results of which were published in the Trans. Roy. Irish Acad., 15,3, 1825. The instrument was also employed by R. Finlay in the rocket experiments to determine the distance between Armagh and Dublin in 1838 (see T.R. Robinson, Trans. Roy. Irish Acad., 19, 121, 1839). A comment by T.R. Robinson in 1844 on the condition of the instrument is worth noting: "The West equatorial while in the hands of Mr. Troughton was injured by a frost which condensed on it moisture charged with the sulphorous vapours of the London smoke, and spotted it all over. I fear this change has increased with time, and may at last corrode the brass to some depth. I would therefore suggest that it should be painted and varnished, which has been found sufficient to arrest such an injury in other instruments". AI10* Meridian Marks. J.A. Hamilton was responsible for the original marks. From the Observatory Minute Book for 6 Oct 1848, p.2: South meridian mark repaired, substituted a massive iron ring for the former copper one. The north mark, a light arch, is singularly so chosen for a purpose where the utmost steadiness is required. IA11* Sextant by Dollond with case. Containing two lenses, one lens cap and three filters. IA12* Refractor by Dollond, London. No object glass, one internal eyepiece lens, internal diameter of mahogany tube: 2.75 inches. IA13* Refractor by Dollond, London. 2.75 inch object glass, tripod stand, no eyepiece. IA14* Pocket telescope. 1.5 inch diameter, with 4 eyepiece lenses on small turret wheel. IA15 Metal rod. 18 inches long. IA16 Two connected metal rings. IA17* Part of Pyrometer by J. Whitehurst, Derby. IA18* Barometer by P. Newman, 122 Regent St., London. IA19* Celestial Globe on Stand by H.&L.H. Bardin. c.1800. 18" diameter. The inscription reads: To the Rev. Nevil Maskelyne, DD, FRS Astronomer Royal this new British Celestial Globe containing the Positions of nearly 6000 stars, clusters, nebulae, planetary nebulae, &c. correctly laid down to the present period from the latest observations and discoveries by Dr Maskelyne, Dr Herschel, The Revd. Fr. Wollaston, &c. &c. respectfully dedicated by his most obedient humble Servants H.&L.H. Bardin. Sold by W. & S. Jones, Holborn, London. IA20* Celestial Globe by J. & W. Cary. IA21* Brass Orrery by Gilkerson and Co., Tower Hill, London c. 1810. IA22* Two Terrestrial Orreries. IA23* Equatorial Theodolite by G. Adams, London. IA24* Gregorian Telescope by G. Adams. No.60. IA25* Portable Altazimuth Telescope by Gilkerson & Co. 2" aperture. IA26* Transit Instrument by Thomas Jones. 1827. 3-inch aperture, 63 inches focal length. This instrument was described by T.R. Robinson in the Armagh Observations for 1828 and 1829. Power of instrument: 120 diameters, changed in 1840 to 195 diameters. "The transit was supported by piers of Armagh marble, 6' high, 24" by 18" at their base, 12" by 18" at top, secured by cement and bronze dowels to a block of the same marble, 6' by 5' and 10" thick. A small circle made by Mr. Gardner and divided by Mr. Grubb has been attached to the axis of the Transit. The tube and the cones of the axis are connected by tension-screws, as described by Sir James South (Phil. Trans. Roy. Soc., 1826, Pt.III, p. 423); the braces shown in his figure are not applied. The axis is 30" long, and the central ball 9" in diameter. The pivots are 1" diameter, of bell-metal. The instrument has, at the eye-end, Troughton's altitude circles, but a circle 8.5" diameter, was later attached by Grubb of Dublin, to the perforated end of the axis, in 1844. The Y's are carried by strong semicircular disks of brass 13" diameter and 1" thick, let into the piers flush with their surface. The adjustment for level is made at the western Y by check-nuts on a screw; that for azimuth at the other Y. The surfaces of the Y's are inclined at 60 degrees instead of 90 degrees, to reduce the effects of friction, and are faced with Brazil pebble. The counterpoise levers were originally similar to those which Troughton had applied to the Greenwich transit, however, they were seen to be unsuitable. The rollers were removed from the annular levers and replaced by gibbets, from which were suspended Y's, faced with agate, to take the projecting parts of the pivots". In October 1832, Thomas Jones came to Armagh to re-divide the circle, and Robinson availed himself of the opportunity to have the pivots reground. The pivots were again examined on 25 May 1839 on the occasion of a visit by Mr Dent. The Transit Instrument and Jones Mural Circle were used by Robinson to compile the publication: "Places of 5345 Stars observed from 1828 to 1854 at the Armagh Observatory". The main purpose of this catalogue was to re-determine the positions of the stars observed by James Bradley in the middle of the 18th century, to which a number of other stars, chiefly from Lalande, had been added. Several special investigations were also entered into, such as the determination of longitude of the Observatory by chronometers, rocket signals and other methods (see Mem. Roy. astr. Soc., 4, 293-304; Trans. Roy. Irish Acad., 19, 110-146). IA27* Mural Circle by Thomas Jones. 1831. Diameter: 56"; 3-inch aperture telescope of 63" focal length. The telescope was a duplicate of that of the Jones transit instrument. This instrument was described by Robinson (see Mem. Roy. astr. Soc., 9, 1835) where he mentions the peculiar shape of the pier: "built of Armagh marble, joggled together, and cemented with mortar of marble lime and Loughneagh sand, which in a few years attains the hardness of compact limestone. The bracing circle is continuous and clasps each radius rather than being screwed to it. The axis is 36" long with steel pivots. The motion-wheel, a uniform plate of copper, is 55.5" extreme diameter. The reading microscopes are of unusual size, being 24.5" from the micrometers to the object glasses which are triple achromatics by Tulley of 0.75" aperture and 7" focus". Robinson composed a paper on the constant of refraction from observations with this instrument (see Trans. Roy. Irish Acad., 19, 177, 1843). In 1848, Robinson formulated the plan of converting the mural circle into a transit circle, by adding to it a second axis supported on a pier, and substituting a telescope of larger aperture (7") and about the same focal length as the original telescope. The new telescope was made by Thomas Grubb of Dublin and was attached to the circle, but without a second pier. Two small collimators were mounted in the same room on iron pillars, north and south of the circle. These improvements were completed in 1862 and a new series of observations of stars selected from those observed by Lalande at the close of the 18th century was then commenced. IA28 Eyepiece with attached micrometer by Thomas Jones. For use with the transit instrument or mural circle? IA29 Range-finder telescope by Thomas Jones. 1-inch aperture with scale along length of tube. IA30* Syphon Barometer Pendulum by Romney Robinson. Used to correct the clock rate for changes in the atmospheric pressure (see Mon. Not. Roy. astr. Soc., 2, 40, 1831). IA31* Discharge Tubes. Set of six intricately-made discharge tubes. IA32* 15-inch Newtonian-Cassegrain Reflector by Grubb. 1835. This telescope was made by Thomas Grubb of Dublin and was equatorially mounted, with clock movement, under the East dome. The mirror was of speculum metal. The Earl of Rosse made and presented the Observatory with a duplicate of the mirror in 1843. In the Observatory Minute Book for 1843 it was noted that two micrometers were applied to the declination circle, its cast iron axis was replaced with a stronger one, and a machine to polish the specula was completed. The mirror cell was, it is believed, the first ever to employ a compound triangular system of balanced levers to support the main mirror (see Proc. Roy. Soc., 135, p.iv, 1932 and H.C. King in 'The History of the Telescope', Griffin & Co., 1955). T.R. Robinson spoke well of this telscope as the resolving power was good enough to separate some difficult double stars (see Phil. Trans. Roy. Soc., 159, 132, 1869). The mirror was re-figured in 1871 by Grubb. A good observation of the 1882 transit of Venus was obtained (see Copernicus, 3, 18, 1882). The only parts of the instrument remaining at the Observatory are parts of the clockwork drive, the mirror cell, secondary mirror (3-inch diameter), and equatorial mounting. IA33* Celestial Globe on stand by W. Newton, Son & Berry. 1836. 16-inches diameter, with compass points at base. The inscription reads: Newton's new and improved Celestial Globe, on which all the Stars are taken from the elaborate and most improved Catalogue of Piazzi, the Nebulas from Bode and the Double Stars and those with proper motions from South. The Right Ascensions & Declinations of the whole having been recalculated and accurately laid down for the year 1840. By Mr W Newton. Manufactured by Newton, Son & Berry, Chancery Lane, London. Published 1st May, 1836. IA34* Brass Draw-tube of telescope with graduated circle. No lenses, 1-inch thread for eyepiece, diameter of main brass tube: 3-3/16 inches, total length 22". Part of Tulley telescope? IA35.1* Cup-anemometer by Munro. 1846. The Robinson Cup-anemometer was first erected on the roof of the Observatory in 1846. However, regular meteorological observations had commenced in 1833. In 1867, when the Board of Trade decided to establish seven first class meteorological stations throughout the British Isles, where complete sets of self- recording instruments, working by photography, should be in action day and night without interuption, Armagh Observatory was selected as one of the stations. From a note in the Observatory Minute Book, the clock work of the registry of the anemometer had been in action since March 1847. A description of the anemometer appeared in Trans. Roy. Irish Acad., , 22, Pt.1, Science, 155, 1855. The results of Robinson's researches into the constants of the cup-anemometer were given in Phil. Trans. Roy. Soc., 169, 777, 1878 and 171, 1055, 1880. 2* Wind-speed Recorder by R.W. Munro, London. 1870. Serial number 11. IA36* Orrery by Phillips. c. 1840s. IA37 Two finder telescopes. IA38* Micrometer. IA39* Clock Drive Governor in square-pyramid box. IA40 Part of pendulum. IA41 Concave mirror in mount. IA42 Two lenses in brass mounts. IA43 2" diameter Lens in mount, surfaces ground. IA44* 4" diameter Split-lens in brass mount. T. Blunt, London. IA45 Eyepiece holder. 1-5/8" diameter and 3" diameter. IA46 Eyepiece mount, push fit tube, 1" diameter. IA47 Eyepiece holder. 3-5/8" diameter thread, 6.75" long. IA48 Self-centring eclipse carriers for slides. R.R. Beard. IA49 1/lO" Wollaston Doublet. IA50* Box containing bronze cylinder and glass screen. IA51 4" diameter condenser lens. IA52 4" diameter lens in metal holder. IA53 4" diameter lens. IA54 Metal flange. 7" diameter. IA55* Thermometer by Troughton and Simms. "Gift of General Sabine" written on reverse. IA56 Eyepiece, 1" diameter lens in 2" diameter tube, 4" long with lamp inside, terminals at front end, lens off-set. IA57 Condenser lens in brass mount. 3-7/8" diameter. IA58 Micrometer eyepiece with saw-tooth slide. 7/8" diameter, 7" long. IA59 Eyepiece holder. 1" diameter, 5" long. IA60 Eyepiece, brass tube with one lens. 1-9/16" diameter lens, 2" long. IA61 Draughtsman's rule by Ertel & Sohn in case. 13" long. IA62* Object Glass, 7" diameter. IA63* Electric Chronograph by Knoblich of Altona. 1865. In 1865, T.R. Robinson purchased and presented to the Observatory this electric chronograph for registering transits proving of great value in increasing the accuracy of the work. The clock movement was altered by Grubb in 1868. As a specimen of the work, Robinson published in 1879 the "Places of One Thousand Stars observed at the Armagh Observatory" (see Trans. Roy. Dublin Soc., Ser.2, 1, 101, 1879). IA64* Heliostat. c.1871 6.75 inches in diameter, mirror: 1-7/8 inches diameter. IA65* Two thermometers. (Inv.No.275) IA66 18 inch Reflector by G. Calver. 1883 This reflector was made for Colonel Tupman of Harrow at a cost of 800 pounds. John Pierce of the Wexford Engineering Works bought it for 200 pounds to replace his 8 inch Wray refractor. It was later given to Revd. W.F.A. Ellison, a former Director of the Observatory, as a gift. Ellison handed over the telescope to the Observatory by a deed of gift made on the 3rd January 1919. Ellison lightly re-figured the mirror and made some studies of stellar spectra with it. IA67.1* 10 inch Equatorial Refractor by Grubb. 1885. Dr. Dreyer started a fund to set up a telescope in T.R. Robinson's memory. The fund reached the sum of 100 pounds. With this and a grant of 2000 pounds from the Government, the 10 inch refractor and a dome for it were purchased. The telescope was mounted on 28th July, 1885 and regular work with it began in September 1885, the first programme involving a re-examination of some nebulae which had been suspected of change (see Dreyer, Mon. Not. Roy. astr. Soc., 47, 412, 1886). After 1893, micrometrical measurements of double stars, together with occasional work on phenomena such as the 1895 transit of Mercury were carried out (see Mon. Not. Roy. astr. Soc., 55, 213, 1895). W.F.A. Ellison was assisted by his son Mervyn, later Director of Dunsink Observatory, in double star observations. The pairs in Holmes' and Sheiner's catalogues were re-examined. Results were published in Mon. Not. Roy. astr. Soc., 85, 1021, suppl., 1925; 87, 465, 1927; 89, 138, 1928. During the course of this work, Ellison discovered a number of new double stars. One of the most energetic stellar flares ever observed was seen by Dr A D Andrews with this telescope in 1969 - it may still be a record to this day (see "Out of the Zenith: Jodrell Bank 1957- 1970" by B. Lovell, Oxford University Press, 1973; and Nature, 222, 1126 & 1129, 1969). IA67 .2* Filar Micrometer by Grubb. 1885. This micrometer was presented to the Observatory by Grubb as a contribution towards the Robinson Memorial Fund set up by Dreyer. It was for use with the 10" Grubb refractor. .3* Small Micrometer for use with 10" Grubb refractor. IA68* Micrometer by Troughton & Simms, London, in case. With three lenses and two filters. IA69 Electric photo-lantern. Butcher. IA70 Box with filter on projecting tube. Filter diameter: 7/8". IA71* Thermometer on ivory mount by J. Newman, London. IA72* Chronometer by W.B. Crisp, London. c.1891. Serial number 8038 IA73* Micrometer-microscope by Troughton & Simms. 1899. The Royal Society provided 70 pounds towards purchasing this measuring machine. A survey of the positions of all stars and other objects within 25 arc minutes of the centre of the spiral galaxy in Triangulum, Messier 33, was conducted using photographic plates exposed by Isaac Roberts (see Proc. Roy. Irish Acad., 25A, 1904). IA74* Pocket Barometer and Altimeter. Thomas Armstrong & Bros., Manchester and Liverpool. IA75* Meridian Calendar. Late 19th century. IA76* Pocket Watch. Early 20th century. IA77 Henry Draper Eyepiece. 1" aperture, 2" long. Believed to be an eyepiece used in the compilation of the Henry Draper spectral classification catalogue. IA78* Binocular Microscope. IA79 6" Refractor by W.F.A. Ellison. 1920. In 1921, Ellison mounted this refractor in the east dome, the equatorial and clock drive being those of the 15" Grubb reflector which had been there since T.R. Robinson's day. IA80* Astro Compass in case. MK2 GA/1174 2-4 IA81* Ship's navigation equipment. Model: BETEC 9. IA82* Mechanical Calculator. Brunsviga, Model No. 20, Serial No. 260075. IA83 Lena, mount and filaments. Short Lens Type G.45. Ref. No. 14A/1399*. IA84 Mercury contact. IA85 Stopwatch 1/10 sec. VC/2534, Serial No. 12509. IA86* Armagh-Dunsink-Harvard Telescope. 32"/35.6", f/3.75 Cassegrain Schmidt. The ADH telescope was of the Baker-Schmidt C4 type, being designed by Professor James Baker of Harvard University (see Proc. Amer. Phil. Soc., 82, 339-349, 1940). It came into operation in 1950, and in 1951 the then world's largest objective prism, 33" in diameter, was provided from funds contributed by Harvard and the Department of Astronomy at Queen's, Belfast (see Sci. Amer., p.46, July 1952). The telescope was placed on the Fecker mounting of the 24" Bruce refractor at the Boyden Station of the Harvard Observatory in Bloemfontein, South Africa. The two- mirror and corrector system give a flat field and reduced tube length (168") compared with the classical Schmidt telescope (see H.C. King, "The History of the Telescope"). Among the objects studied with photo- graphs from the ADH have been globular star clusters, cluster Cepheids, and the Magellanic Clouds.The ADH optics are currently at Dunsink Observatory, though still jointly owned by the two Irish Observatories. IA87* 12"/18" Armagh Schmidt Telescope. The Calver reflector was converted into a Schmidt telescope in 1950. The Royal Society provided a grant for the conversion of the optical parts by the firm of Cox, Hargreaves and Thomson, who also provided a synchronized drive. The mounting of the Calver was retained. Through a gift from Mr. T. Scott of Armagh, a dome was built (see P. Moore, "Armagh Observatory 1790-1967", p.49). IA88* Rocking-mirror Meteor Cameras. Two rocking-mirror cameras were designed and constructed at the Observatory for the researches carried out by Dr. E.J. Opik (see P. Moore, "Armagh Observatory 1790-1967", p.49/50). IA89 Spectroscope by E.B. Armstrong. IA90 Iris-diaphragm Photometer. c.1955. This instrument, by Sartorius, was used to determine the magnitudes of star images on photographic plates.
Section BIB1 Transit Instrument by James Waugh. c.1793. This 2" aperture transit instrument was employed for making observations of the Sun, Moon and standard stars commencing in July 1793 and continuing until 1827 when the instrument was dismounted. Some results were published in Trans. Roy. Irish Acad., 11, 25-44. Some observations of Moon culminating stars were made between 1795 and 1804, and a number of differences of right ascension of pairs of stars observed in 1802 and 1803 at Greenwich and Armagh on the same night, were intended to improve the accuracy of the Armagh results (see Dreyer, p.6). Dr Hamilton also made a series of measurements of the Sun's apparent diameter between 1794 and 1795 in order to test the accuracy of two micrometers by Dollond (see Trans. Roy. Irish Acad., 10, 109-117). The transit was sold to Mr Sharpe of Dublin (Observatory Minutes for 18 Oct 1827, p.l6). IB2 Variation Compass. c.1796. Note on inventory: Taken by Mr Holmes. IB3 Circumferentor and stand. c.1796. Taken by Mr Holmes. IB4 Clock by Waugh. c.1796. Taken by Mr Holmes. IB5 10' Newtonian Reflector by Sir William Herschel. Acquired before 1819. 10" aperture.(See Stuart, 1819, p.523). This telescope was mounted in the East tower on a stone pier. No trace of the telescope can be found. A Herschel eyepiece is still at the Observatory and may be part of this instrument. IB6 Clock by Sharp. This clock was used in 1838 in the determination of the distance between Armagh and Dublin. It disappeared in the 1970s. IB7 Platinum-wire Micrometer by T. R. Robinson. Sir William R. Hamilton accidentally broke this micrometer (see Irish Astron. Journal, 5, 161, 1959). IB8 Four telescopes. In April, 1918, Revd. C. Faris was authorized to place four telescopes at the disposal of the Lady Roberts' Field Glass Fund for the duration of the war, and in a letter dated 29 April Lady Roberts wrote stating that the instruments would be returned after the end of the war "should circumstances permit" (see M92.11). Registered numbers of telescopes: Z.191, Z.192, Z.193, and Z.194.
Section CIC1 Barometer by Smith, Bath. c. 1796. IC2 Thermometer by Troughton. c.1796. IC3 Thermometer by Dollond. c.1796. IC4 Air Pumps and Receivers. c.1796. IC5 Electrical Machine, brass conductor, battery and jars. c.1796. IC6 Night Telescope. c.1796. IC7 Sundry parts of the old Philosophical Apparatus of Dublin College. c.1796. IC8 Horizontal Collimator by Dollond. Made entirely of glass (see Introduction to the Armagh Catalogue of Stars, p.viii). IC9 Hadley Sextant by Troughton. 10" radius. c.1818. The latitude of Armagh Observatory was found to the nearest second of a degree with this instrument. (See Stuart 1819, p. 525). IC10 Quadrant by Robert Hogg. 35" radius. c.1818. Revd. R. Hogg, deputy at Armagh Observatory, built an astronomical quadrant, with the assistance of James Waugh (see Stuart 1819). An article, possibly by Hogg, on "Solar Spots" appeared in the Newry Magazine, Vol.III, No.17, p.427, 1817. IC11 Transit Instrument by Higgins. c.1818. Referred to in Stuart's Memoirs of Armagh, p.525. IC12 Thermometer by Healy. c.1823. IC13 Self-registering Thermometer. c.1823. IC14 Kater's Hygrometer. c.1823. IC15 Robinson's Chronometer. c.1838. Used in connection with the rocket signal method (see Trans. Roy. Irish Acad., 19, p.l21). A reference appears in Armagh Catalogue of Stars, p.x. IC16 Wind-gauge. c.1839. Noted in the Observatory Minute Book, 12 Nov 1846, p.46: 'Wind gauge ordered in 1839 has been erected, though not with its graphic apparatus - vanes move with 1/3 of the wind's velocity - about to add a clock work apparatus, which will trace on paper, the movement and direction, so that every variation can be referred to - Dr Robinson requested by Government to construct two similar ones for the Observatories of St Helena and Toronto and one for the British Association at Kew.'
Last Revised: 2011 June 27th