Category of Astronomical Heritage: tangible immovable
Dunsink Observatory, Dublin, Ireland

Description

Geographical position

Dunsink Observatory, Dunsink Lane, Castleknock, Dublin 15, D15 XR2R, Ireland

Location

Latitude 53°23’14’’ N, Longitude -6°20’19’’ W, 84m above mean sea level.

IAU observatory code

982

Description of (scientific/cultural/natural) heritage

Fig. 1. Dunsink Observatory (1785) (© Dunsink Observatory)

Dunsink Observatory, an Institute of the Trinity College in Dublin, 8 km northwest of central Dublin, was built in 1783/85, sponsored by Provost Andrews with ┬ú3,000, It was the first building in Ireland specifically constructed for scientific research -- is the oldest scientific institution of Ireland.
Here is the entry for the observatory Dunsink in Thom’s Irish Almanac and Official Directory for the year 1850:

ASTRONOMICAL OBSERVATORY OF THE UNIVERSITY OF DUBLIN, DUNSINK
Astronomer Royal, Sir William Rowan Hamilton, A.M., LL.D.
Assistant Astronomer, Charles Thomson, esq.
This Observatory, endowed by Francis Andrews, esq., LL.D., Provost of Trinity College, and erected in 1785,
was placed, by statute, in 1791, under the management of the "Royal Astronomer of Ireland",
an appointment first filled by Dr. Henry Ussher, and subsequently by Dr. Brinkley, Bishop of Cloyne.
The Institution is amply furnished with astronomical instruments, and is open to all persons interested in astronomical science,
on introduction to the resident Assistant. It is situated in Lat. 53°23’13’’ N, Long. 6°20’15’’ W.

Fig. 2. Dunsink Observatory, planned, but the two wings were not realized by the architect Graham Myers (1785) (© DIAS)

The architect Graham Myers (1746--1801), an assistant of Richard Cassels (1690--1751), designed an aesthetic building -- without ornaments in a functional style. The plan, to add two Palladian-style wings on either side of the main building with smaller domes, was finally rejected.

Fig. 3a. Shortt Chronometer, Dunsink Observatory (© DIAS)

Fig. 3b. Synchronome clock, Dunsink Observatory (© DIAS)

The emphasis of research of Dunsink Observatory was in the beginning in 19th century on positional astronomy besides timekeeping.

Dunsink Observatory was the place where the time standard for Ireland was determined, mentioned several times in James Joyce’s novel Ulysses. The mean solar time at Dunsink was introduced as Dublin Mean Time, the official time in Ireland from 1880 until WWI (cf. GMT); then in 1916, Ireland moved to GMT.

Dunsink Observatory had been under the direction of the Royal Astronomer of Ireland since 1792. It was also affiliated with Trinity College of Dublin -- the Royal Astronomer was an honorary title of the Andrews Professor of Astronomy at Trinity College Dublin (TCD) until 1922. Then in 1940, the Dublin Institute for Advanced Studies (DIAS), School of Theoretical Physics (Schrödinger), was founded, and in 1947, the School of Cosmic Physics (Hermann Brück) was added.

$South Dome for the 12-inch-Grubb Refractor (1868),$

Fig. 4a. South Dome for the 12-inch-Grubb Refractor (1868), Dunsink Observatory (Drawing, Ball, Robert: The Story of the Heavens, 1905)

$12-inch-Grubb Refractor (1868), Dunsink Observator$

Fig. 4b. 12-inch-Grubb Refractor (1868), Dunsink Observatory (Wikipedia 3, John C. Murphy)

The main instrument of Dunsink Observatory was the South Telescope or 12-inch-Grubb, it is a refracting telescope built by Thomas Grubb of Dublin, completed in 1868 under the direction of Prof. Franz Friedrich Ernst Brünnow (1821--1891).

The achromatic lens, with an aperture of 11.75 inches (30cm), was donated in 1862 by Sir James South (1785--1867), a Victorian astronomer and a friend of the Third Earl of Rosse and T. Romney Robinson at Armagh Observatory. James South had a private observatory Campden Hill in Kensington (*1826), and had purchased an objective lens from Robert-Aglaé Cauchoix (1776--1845) of Paris 30 years earlier (mounted by Troughton in 1831, but this was a failure). He had intended it for a large, but troubled equatorial refractor that came to fruition in the 1830s, but was dismantled around 1838.
A mounting, made by Thomas Grubb of Dublin, was exhibited in the Dublin Industrial Exhibition of 1853. Grubb’s Dunsink mounting was a successor to a similar instrument made already in the 1830s for the amateur astronomer Edward Joshua Cooper (1798--1863) of Markree Castle, County Sligo, also with an objective lens, made by Cauchoix of Paris (13.3 inch, 34cm).
The model for the equatorial mounting of the Dunsink South Telescope was similar to that of the Dorpat Observatory (1824), Estonia, a pioneering mounting, introduced by Josef Fraunhofer (also called German mounting).

Famous astronomers of Dunsink Observatory, Dublin

Henry Ussher (1740--1790) was the first Andrews Professor of Astronomy at Trinity College.
Rev. John Mortimer Brinkley (1763/66--1835), Royal Astronomer from 1790 to 1827, Bishop of Cloyne since 1826, worked in stellar astronomy, measured the parallax of some fixed stars, made micrometrical measurements of double stars, and published Elements of Plane Astronomy in 1808.
Ireland’s most famous mathematician, physicist and astronomer Sir William Rowan Hamilton (1805--1865) was appointed as a 21-year-old undergraduate; he started with geometrical optics. Then he developed the formulation of mechanics that today bears his name ("Hamiltonian mechanics"), in several publications in 1834 and 1835. Later he concentrated his investigations on Quaternions (1843, hypercomplex numbers), which are used today, e.g., in computer graphics.
Franz Friedrich Ernst Brünnow (1821--1891) studied in Berlin under Encke, was director of Düsseldorf-Bilk Observatory (1847--1851), Detroit Observatory (at the University of Ann Arbor, Michigan (1854), Vice-Director of Dudley-Observatory in Albany, N.Y., (1859--1860). He became Royal Astronomer of Ireland (1866 to 1874), erected the equatorial telescope and started researches on stellar parallax; he published a Handbook of Spherical Astronomy in 1865 (German edition, Lehrbuch der sphärischen Astronomie, 1851). In 1873, he acquired for the observatory an excellent transit circle.
Hermann Alexander Brück (1905--2000), born in Berlin, studied in Kiel, Bonn and Munich, got his PhD from Sommerfeld. He worked in the Astrophysical Observatory Potsdam (AOP) with his friend Albrecht Unsöld (1905--1995). In 1936, due to the political situation, he left Germany, and was assistant in the Vatican Observatory in Castel Gandolfo. Then he moved to the University of Cambridge (Arthur Eddington), and became Assistant Director of the Cambridge Observatory and John Couch Adams Astronomer. His specialty was solar spectroscopy. In 1947 he got the call as director of the Dunsink Observatory, and director of the Dublin Institute for Advanced Studies (DIAS). He established a program of solar near-UV spectroscopy and photoelectric stellar photometry. Later, in 1957, he became the Astronomer Royal for Scotland in Edinburgh.

History

$Dome for the 12-inch-South refractor (1868), Dunsi$

Fig. 5a. Dome for the 12-inch-South refractor (1868), Dunsink Observatory (Brünnow 1870, plate 3)

$12-inch-refracting telescope (1868), Thomas Grubb$

Fig. 5b. 12-inch-refracting telescope (1868), Thomas Grubb (1800--1878) of Dublin-Rathmines, Dunsink Observatory (photo: Matthew McMahon)

Instruments of Dunsink Observatory, Dublin

12-inch-Refractor (30.5cm) -- South Telescope (f = 18 ft. 10.7-inch = 5.8m), and adjusted to the achromatic lens of 11.75-inch (30cm), made by Cauchoix of Paris (~1830), with a 3-inch-finder (f=26.5-inch).
The South Telescope was donated to Trinity College Dublin by Sir James South (1785--1867), a Victorian astronomer with a private observatory, and a friend of the Third Earl of Rosse and T. Romney Robinson (1792--1882) of Armagh Observatory.
Thomas Grubb (1800--1878) of Dublin-Rathmines, installed the South Refractor in 1868 with an equatorial mounting (exhibited in the Dublin Industrial Exhibition of 1853); the driving clock is powered by a falling weight, and regulated by a centrifugal govenor. In the1930s, the telescope was modernized by valve amplifiers, synchronous motors, and electrically maintained tuning forks.
The acquisition of the South Telescope and the modification with the new lens and new mounting was pushed by Romney Robinson of Armagh. Brünnow started to set up the new telescope.
Description of the South Refractor (Brünnow 1870, p. 1 f).
The 12-inch-Refractor is still used after WWII for photometric observations (Brück 1950)

The Grubb company made 21 refractors of 13 inch (33cm) aperture or greater, also some reflecting telescopes of moderate size; the largest refractor is the 27-inch (68.5cm) telescope (1878) in Vienna University Observatory. Sir Howard Grubb, Parsons & Co in Newcastle-upon-Tyne continued from 1925 to 1985.
Filar micrometer for the South Telescope, made by Pistor & Martins of Berlin (position circle of 7-inch diameter)
Large 8 ft. (old) Transit circle (2.4m), made by Jesse Ramsden & Matthew Berge of London (1808), in the Western meridian hall (used until the beginning of 19th century), used by Brinkley,
cf. Transactions of the Royal Irish Academy, Vol. XII, Pearson’s Practical Astronomy, p. 423 f.

6 ft. Transit circle (1.8m), aperture 4-inch (10cm), made by Ramsden of London (used from the 1780s until 1873), in the Eastern meridian hall
8 ft. Meridian circle (2.4m), aperture 6.28-inch (16cm) with 25 vertical and 2 horizontal wires, and a vertical wire moveable by a micrometer srew, Pistor & Martins of Berlin (1873), in the Eastern meridian hall
Sidereal Clock (No. 2032), regulator clock with dead-beat escapements, made by E. Dent & Co. of London, Strand (~1870s)
Meteorological instruments, examined by Kew Observatory: Barometer, made by Adie, No. 1184,
small Thermometer, Thermometer (external temperature), made by Casella, B.T. 1758
In the 1860s, for navigation a time ball was built at the corner of O’Connell Bridge. In addition, with a telegraph line, several clocks in Dublin were synchronized with clocks in Dunsink Observatory. In the 1880’s, "Dublin Mean Time" was introduced (until 1916, then "Greenwich Mean Time").
38-cm-Reflector (15-inch), made by .... (....), equatorially mounted in the dome on the roof of the main building,
photographic cameras of great light gathering power added (Stroobant 1907), (Brück 1950)
Synchronome high-precision ’free-pendulum’ Clock, Patent No. 187814 (1921), made by William Hamilton Shortt
Vertical Solar Telescope (instead of the old 8 ft. Transit circle)
Cassegrain with a concave and two different convex mirrors (for visual, IR, UV), effective focal length of 90 and 150 feet.
with a 16-inch-coelostat (40cm) on a steel platform on the roof
(Brück 1950)
Large spectroscope with a concave grating from Johns Hopkins University, USA (radius of curvature of 21 ft. = 53cm, and 30,000 lines per inch)
Photoelectric photometer for stellar photometry, made by the Workshop of the Observatory, used with the 12-inch-Refractor
Moll Recording Microphotometer in the laboratory for the photometric analysis of solar and stellar spectra
Fabry photographic photometer for stellar photometry, made by the Workshop of the Observatory, used with the 12-inch-Refractor, recorded on 16-mm-film
Armagh-Dunsink-Harvard-Telescope

Fig. 6a. Dunsink Observatory (1785) (Wikipedia 2.5, Dwmalone)

Fig. 6b. Sir Robert Stawell Ball, 4th Royal Astronomer of Ireland 1874 to 1892 (© DIAS)

Dates in office of the Andrews’ Professors
of Astronomy
- Rev. Henry Ussher 1783 to 1790
- Rev. John Brinkley 1790 to 1827
- Sir William Rowan Hamilton 1827 to 1865
- Dr Franz F.E. Brünnow 1865 to 1874
- Sir Robert S. Ball 1874 to 1892
- Dr Arthur A. Rambaut 1892 to 1897
- Dr Charles J. Joly 1897 to 1906
- Sir Edmund T. Whittaker 1906 to 1912
- Dr Henry C. Plummer 1912 to 1921
The dates in office of the Senior Professors
of DIAS at Dunsink Observatory:
- Dr Hermann A. Brück 1947 to 1957
- Dr Mervyn A. Ellison 1958 to 1963
- Dr Patrick A. Wayman 1964 to 1992
- Dr Evert J.A. Meurs 1994 to 2007
Fig. 7. Dunsink Observatory (1785) (© DIAS)

Directors of Dunsink Observatory, Dublin

The chair Andrews Professorship of Astronomy was associated with the director of Dunsink Observatory
during the time that the Observatory was part of Trinity College Dublin (TCD).
Dates Name Other titles Notes
- 1783 to 1790 Rev. Henry Ussher (1741--1790), the first Director of Dunsink
- 1792 to 1827 Rev. John Mortimer Brinkley (1763/66--1835), Royal Astronomer of Ireland (from 1793)
- 1827 to 1865 Sir William Rowan Hamilton (1805--1865), Royal Astronomer of Ireland
- 1865 to 1874 Franz Brünnow (1821--1891), Royal Astronomer of Ireland
- 1874 to 1892 Sir Robert Stawell Ball (1840--1913), Royal Astronomer of Ireland.
  In 1892 became Lowndean Professor of Astronomy and Geometry at Cambridge
- 1892 to 1897 Arthur Alcock Rambaut (1859--1923), Royal Astronomer of Ireland.
  In 1897 became Radcliffe Observer at Oxford
- 1897 to 1906 Charles Jasper Joly (1864--1906), Royal Astronomer of Ireland
- 1906 to 1912 Sir Edmund Taylor Whittaker (1873--1956), Royal Astronomer of Ireland.
  In 1911 became a professor at Edinburgh
- 1912 to 1921 Henry Crozier Keating Plummer (1875--1946), 9th Andrews Professor of Astronomy,
  8th Royal Astronomer of Ireland. In 1921, professor of mathematics at the Artillery College in Woolwich
- 1921 to 1936 Charles Martin
- 1936 to 1947 Vacant -- No astronomical work was done
Fig. 8. Hermann Alexander Brück (1905--2000) (© MacTutor, DJF/JOC/EFR, Creative Commons Attribution-ShareAlike 4.0)
- 1947 to 1957 Hermann Alexander Brück (1905--2000), Senior Professor,
  Director of DIAS School of Cosmic Physics, in 1957, Astronomer Royal for Scotland
- 1958 to 1963 Mervyn Archdall Ellison (1909--1963), Senior Professor,
  Director of DIAS School of Cosmic Physics
- 1964 to 1992 Patrick Arthur Wayman, Senior Professor, Director of DIAS School of Cosmic Physics,
  10th Andrews Professor of Astronomy (TCD; Honorary)
- 1994 to 2007 Evert Meurs, Senior Professor,
  Head of DIAS Astronomy Section
- 2007 to 2018 Luke Drury, Senior Professor,
  Director of DIAS School of Cosmic Physics
- 2018 to present Peter T. Gallagher, Senior Professor, Head of DIAS Astronomy and Astrophysics Section,
  Adjunct Professor of Astrophysics (TCD).

State of preservation

The observatory is in good condition.

One step forward in the direction to the Unesco application was made in 2023: Irish astronomers hope stars align for new North-South collaboration (Link) -- An event to celebrate an all-island Irish astronomy initiative will see the community honour one of their own, renowned astronomer Martin Rees.

Comparison with related/similar sites

Fig. 9a. Dunsink Observatory (1785) (Bruennow 1870, cover)

Fig. 9b. Dunsink Observatory (1785) (© DIAS)

Dunsink Observatory is a one dome observatory building (in the East is the tower with a massive fundament); a round building in the west is the meridian room. The result is a L-shaped ground pattern. The South dome was added later (1868) -- like in Armagh.

The buildings of Dunsink Observatory Dublin (1785), Seeberg Observatory, Gotha (1788) and Armagh Observatory (1790) represent a revolution in observatory design (Gotha is not preserved); the earliest building with a dome -- King’s Observatory, Kew (1768) -- should also be mentioned. The characteristic feature of an observatory, the dome, dominating the architecture, appears for the first time in these observatories. But in Dunsink the original dome (1785), rotatable on wheels on a circular rail; was replaced in 1892 by a slightly larger one with a diameter of 5.5m. The next famous early dome which are well preserved in its original shape is in Tartu Observatory, Estonia (1802) -- a cylindrical dome, and Göttingen Observatory, Germany (1803/16).

In summary, Dunsink is important because of three innovations (Müller 1992): first, the observatory is not in the historical city center, but a considerable distance from the city center (8 km); second, a hemispherical dome in a central arrangement; thirdly, a thick pillar for the instrument in this dome, which is surrounded by a circular wall and thus isolated.

Fig. 10. Plaque for the Grubb firm, which started in 6 Canal Road, Dublin, in 1830, later in Dublin-Rathmines (photo: William Fagan, 2017, www.macfilos.com)

The Grubb firm in Dublin-Rathmines

"The 19th century has often been referred to as the golden age of astronomy in Ireland. It was a period of great innovation in telescope design and in astronomical discovery, in which Irish scientists played a leading role, and one quite disproportionate to the size of the Irish scientific community" (Butler 1994). The highlight is Lord Rosse’s telescope in Birr Castle, which was for over seventy years the largest telescope in the world -- before the erection of the large reflectors Mount Wilson and Mount Palomar in California. Especially important is the firm Grubb in Dublin-Rathmines, which supported Irish observatories like Dublin, Armagh, Crawford Observatory in Cork, with remarkable telescopes.

"This company, originally founded by Thomas Grubb, and later continued by his son Howard, was responsible for many important innovations in telescope and instrument design which subsequently became commonplace and was the only Irish scientific instrument company to achieve international status."
Grubb was also known for constructing accurate electrically driven clock drives for equatorial mounted telescopes; especially in Dublin Observatory we can see a part of the early development. "Thomas and Howard Grubb were particularly well known for their large reflecting telescopes, for which they pioneered the use of equatorial mountings with clock drives. Such improved mountings enabled the telescope to be pointed at any object above the horizon and to maintain its position in the field of view for an extended period."
"The Grubb company from its inception in the 1830’s, survived until quite recently as Grubb & Parsons of Newcastle Upon Tyne, where it built the Anglo-Australian Telescope, erected near Sydney, and the William Herschel Telescope, erected in the Canary Isles" (Butler 1994).

Threats or potential threats

no threats

Present use

In 2012, the observatory is used mainly for public outreach, small workshops and conferences, and as visitor accommodation for the Dublin Institute for Advanced Studies. Open nights for star gazing are held twice monthly.

Fig. 10a. South dome of the Dunsink Observatory (1785) (© DIAS)

$12-inch-Grubb Refractor (1868), Dunsink Observator$

Fig. 10b. 12-inch-Grubb Refractor (1868), Dunsink Observatory (1785) (© DIAS)

Astronomical relevance today

Observatory is part of Dublin Institute for Advanced Studies (DIAS), and is active in cutting-edge astrophysical research.

References

Bibliography (books and published articles)

Ball, Robert: The Story of the Heavens. London: Cassell & Company Ltd. 1905.
Brück, Hermann & Mary Brück: The solar installation of Dunsink Observatory. In: Vistas in Astronomy 1 (1955), p. 430-437.
Clerke, Agnes Mary: "Cooper, Edward Joshua." In: Stephen, Leslie (ed.): Dictionary of National Biography, Vol. 12. London: Smith, Elder & Co 1887.
Elliott, Ian: "Cooper, Joshua Edward." In: Hockey, Thomas; Williams, Thomas & Virginia Trimble (eds.): Biographical Encyclopedia of Astronomers. New York: Springer Science & Business Media 200, pp. 250--251.
Glass, Ian S.: Victorian Telescope Makers -- the lives and letters of Thomas and Howard Grubb. Bristol, UK: Institute of Physics 1997.
Glass, Ian S.: "Grubb, Thomas." In: Hockey, Thomas; Williams, Thomas & Virginia Trimble (eds.): Biographical Encyclopedia of Astronomers. New York: Springer Science & Business Media 2007, pp. 447--448.
Salmon, Philip: "Cooper, Edward Joshua (1798--1863), of Markree Castle, co. Sligo and Boden Park, co. Westmeath." In: Fisher, D.R. (ed.): The History of Parliament: the House of Commons 1820--1832. Cambridge, UK: Cambridge University Press 2009.
Steinicke, Wolfgang: Observing and Cataloguing Nebulae and Star Clusters: From Herschel to Dreyer’s New General Catalogue. Cambridge, UK: Cambridge University Press 2010, pp. 137, 252.
Thom, Alexander: Thom’s Irish Almanac and Official Directory for the year 1850. Dublin: Alexander Thom Printer and Publisher (7th ed.) 1850, p. 258, entry for the observatory Dunsink.
Ussher, Henry: Account of the Observatory Belonging to Trinity College, Dublin. In: The Transactions of the Royal Irish Academy 1 (1787), p.~3--21.
Wayman, Patrick A.: The South Telescope of Dunsink Observatory. In: Irish Astronomical Journal 8 (1968), issue 8, p. 274.
Wayman, Patrick A.: Dunsink Observatory 1795--1985. Dublin: Dublin Institute for Advanced Studies and the Royal Dublin Society 1987.