Birr Castle Research Articles

Method to observe Jupiter’s radio emissions at high resolution using multiple LOFAR stations: a first case study of the Io-decametric emission using the Irish IE613, French FR606, and German DE604 stations

ABSTRACT The Low Frequency Array (LOFAR) is an international radio telescope array, consisting of 38 stations in the Netherlands and 14 international stations spread over Europe. Here, we present an observation method to study the Jovian decametric radio emissions from several LOFAR stations (here Birr Castle in Ireland, Nançay in France, and Postdam in Germany), at high temporal and spectral resolution. This method is based on prediction tools, such as radio emission simulations and probability maps, and data processing. We report an observation of Io-induced decametric emission from 2021 June, and a first case study of the substructures that compose the macroscopic emissions (called millisecond bursts). The study of these bursts makes it possible to determine the electron populations at the origin of these emissions. We then present several possible future avenues for study based on these observations. The methodology and study perspectives described in this paper can be applied to new observations of Jovian radio emissions induced by Io, but also by Ganymede or Europa, or Jovian auroral radio emissions.

William Parsons, 3rd Earl of Rosse: Astronomy and the Castle in Nineteenth-Century Ireland

Historians of astronomy are familiar with Lord Rosse (1800-1867), his Leviathan, and his discovery of the spiral structure of nebulae. For many though, Rosse is an example of astronomy on the periphery, of an enthusiastic Irish earl constructing the world's largest telescope in a cloudy corner of Ireland. Besides the observational data it generated, what influence did such an undertaking have on the wider astronomical community? What were Rosse's motivations and how did his work play out again the background of a post-Union Ireland? These questions motivate a recent collection of essays on Rosse, edited by the historian of Irish science Charles Mollan, and their answers go far to situate Rosse in the rich scientific and political culture of the middle third of the nineteenth century.The essays in the collection run the gamut from surveys of Rosse's astronomical work to his involvement in Irish politics. As the first two essays in the collection illustrate, Rosse came from a tradition that emphasized practical education and engineering. The current Earl and Countess of Rosse present the history of the Rosse family and of their ancestral holding, Birr Castle. This is followed by an examination by Irish astronomer Trevor Weekes of Rosse's educational background and the influence it had on his eventual astronomical endeavours. The seeds were planted early, Weekes maintains, by his home education and his father's scientific interests. His marriage to Mary Field (1813-1885) and her inheritance allowed him the financial freedom to pursue his interests on a grand scale. Lady Rosse's own technical prowess is not disregarded; the collection's third essay outlines her life and scientific achievements, primarily in photography.The next essays help place Rosse in the Irish landscape, physically and politically. Margaret Hogan chronicles his career as a Protestant landlord of a primarily Catholic constituency, including his reluctant political service and his local and legislative relief attempts during the Great Irish Famine (1845-1852). Andrew Shield portrays Rosse as loyal to his class and to English Union but also emphasizes his tact in navigating delicate situations like the schism that affected his local Catholic parish or his increasingly conservative stance on land questions in the face of Irish unrest. A useful addition to these papers would have been a map of Birr and its environs for readers unfamiliar with the area.Mollan makes perhaps the most interesting claim of the collection in his essay on Rosse as an engineer, suggesting that engineering was Rosse's primary concern and that he was less interested in astronomical observation than in the challenges of constructing very large telescopes. …

Rosse, Robinson and Rambaut: Creating a Regime of Observing at Birr Castle, 1840–1850

The decade of the 1840s was arguably the most important period in the long history of astronomy at Birr Castle in Ireland; it included the building of the famous 6-ft reflector and some of its most influential achievements. It was also a challenging time for Lord Rosse on several fronts and the future of the great telescope as a productive research instrument was far from secure. That a steady programme of work was achieved owed no small debt to T. R. Robinson and his nephew W. H. Rambaut, who became an observing assistant to Lord Rosse and used all the current instruments. Rambaut’s observing notebooks are a valuable and revealing record of the observatory work during the critical transition from the completion of the 6-ft telescope to its routine use. The early work on observing nebulae was often done in collaboration, with more than one observer present, and was animated by the pursuit of resolution and the detection of spiral structures. As the programme of observing settled into a more methodical recording of the forms of the nebulae, Rambaut’s work seemed less relevant to the active astronomers at Birr and his notes might even be modified as they were edited for publication.

Observations of Low Frequency Solar Radio Bursts from the Rosse Solar-Terrestrial Observatory

The Rosse Solar-Terrestrial Observatory (RSTO; ) was established at Birr Castle, Co. Offaly, Ireland (53°05′38.9″, 7°55′12.7″) in 2010 to study solar radio bursts and the response of the Earth’s ionosphere and geomagnetic field. To date, three Compound Astronomical Low-cost Low-frequency Instrument for Spectroscopy in Transportable Observatory (CALLISTO) spectrometers have been installed, with the capability of observing in the frequency range of 10 – 870 MHz. The receivers are fed simultaneously by biconical and log-periodic antennas. Nominally, frequency spectra in the range of 10 – 400 MHz are obtained with four sweeps per second over 600 channels. Here, we describe the RSTO solar radio spectrometer set-up, and present dynamic spectra of samples of type II, III and IV radio bursts. In particular, we describe the fine-scale structure observed in type II bursts, including band splitting and rapidly varying herringbone features.

THE M51 MYSTERY: LORD ROSSE, ROBINSON, SOUTH AND THE DISCOVERY OF SPIRAL STRUCTURE IN 1845

In April 1845 Lord Rosse discovered the spiral structure of M51 with his 72-inch reflector at Birr Castle. Already in March the new telescope had been pointed at the object in Canes Venatici, later nicknamed the 'Whirlpool Nebula'. Two experienced astronomers were present: Sir James South and the Reverend Thomas Romney Robin-son. The problem is that there is no record that they noticed the spiral structure, even though it was immediately seen by Lord Rosse the next month. The solution presented here is based on evidentiary facts, highlighting the nine-teenth century astronomical praxis. Focal points are bias, fantasy and a sometimes fatal conspiracy of eye and brain.

The Nineteenth-Century Spiral Nebula Whodunit

The discovery of the first spiral nebula was a milestone in the history of astronomy, but the initial observations of it are shrouded in mystery. The discovery came within months of the commissioning of the Third Earl of Rosse’s very large 72-inch optical telescope at Birr Castle in the center of Ireland. Unfortunately, no observing records have survived, and while there is no doubt that the observations took place in the spring of 1845, there is some uncertainty as to whom was actually present when the discovery was made. The construction of the Earl’s telescope (the Leviathan) was a magnificent achievement, since it was entirely of his design, built with his own funds, and constructed by his own workers who were literally taken “from the plough” on his estate. The summer of 1845 saw the first appearance of the Irish Potato Famine of 1845–1848, which would seriously curtail astronomical activity when Lord Rosse’s 72-inch telescope was in prime condition.

Resolving the nebulae: the science and art of representing M51

Astronomy has a long tradition of translating data into different visual representations and scholars have noted a division between ‘pretty pictures’ and scientific images. A series of drawings and engravings of M51 derived from Lord Rosse’s observations at Birr Castle and Hubble Space Telescope images of the same object offer an opportunity to examine shifts in the object’s representation within a given period, as well as over the long history of observing it. This demonstrates both the consistent interest of astronomy in structure and improved resolution, as well as the subjective treatment of light and color. Furthermore, while the distinction between ‘pretty pictures’ and scientific images offers a starting point for analyzing the translations within a given period, the line between the two blurs, suggesting the complexity of aesthetic choices within astronomical images.

Restoration of the Great Telescope at Birr Castle Demesne, Ireland

Restoration of the Great Telescope at Birr Castle Demesne, Ireland

Restoration of the Great Telescope at Birr Castle Demesne, Ireland

Restoration of the Great Telescope at Birr Castle Demesne, Ireland

Miscelanea Structura Curiosa: The cross-currencies of Vitruvius Hibernicus

Abstract A fascinating collection of mid-eighteenth-century drawings of garden follies, fountains and architecture has recendy surfaced in the Earl of Rosse's library at Birr Castle.1 The folio, which is intriguingly entitled Miscelanea Structura Curiosa, was prepared by Samuel Chearnley and his patron, Sir Laurence Parsons, 3rd Bart. (a direct ancestor of the present Earl), and has waited for nearly 250 years to be re-introduced to Ireland's present-day community of architects and garden historians (figure 1).2 This hitherto unknown set of drawings (and its natural links to the demesne of Birr Castle) put eighteenth-century Ireland on the map as an important center of architectural, horticultural and scientific pursuits.

J. D. Bernal, F. R. S.: some Irish influences

Ann Synge’s essay on Bernal’s family, school and university background resurrected some questions which had first occurred to me when reading Bernal’s Science in History in the late 1950s. We have the Sherlock Holmes problem of the ‘dog that didn’t bark’: the paucity of Irish references. Why the blind spot regarding what should have been a rich source of material for the Bernal ‘science and society’ paradigm? He references Parsons, but labels him British, and is apparently unaware of the richness of the connection between Parsons and Birr Castle, which he visited as a boy. Ann Synge’s essay re-opened the question for me, prompting a visit to Cambridge to look at the Bernal papers, with a view to gaining insight into the nature and extent of the specific Irish influences on Bernal, if any, and complementing Ann Synge’s research into the Bernal family background. Other questions arise: what was the totality of factors influencing the education decision which led to Bedford and Cambridge?- How good was Bernal’s own awareness of his ‘anomalous position’, as expressed in his 1955 self-assessment, where he describes his background as ‘small farmer’? What degree of political understanding lay behind the 1920 family row, and how did this relate to his emerging Cambridge Marxism? How near was he to joining the British Army? In the following sections I address some aspects of these questions.

THROUGH THE INFRARED WITH LOGBOOK AND LANTERN SLIDES - A HISTORY OF INFRARED ASTRONOMY FROM 1868 TO 1960

Only nine years after Kirchoff published his radiation laws and eleven years before Stefan published the fourth power of absolute-temperature law, the fourth Earl of Rosse made the first infrared measurements of any astronomical body other than the Sun. He observed the Moon with a thermopile and the three-foot reflector at Birr Castle in 1868 (Rosse 1869, 1870, 1873). I begin this history of infrared astronomy with his work because he introduced two techniques, one of which was used for 80 years and the other, in modified form, is still used today. Filters that isolated infrared wave bands and were opaque to visible light did not exist, and so he conceived of using a plate of glass as a filter. By differencing the galvanometer readings with and without the glass and suitably correcting the glass readings for reflection losses, he measured the infrared flux from the Moon. This technique I will call subtractive filtering, and it was used until 1950. His first measurements were made with a single thermopile, and he discovered immediately that the galvanometer deflections were strongly influenced by changing telescope temperatures and air temperatures. He then conceived of using two identical thermopiles, one connected in opposition to the other, both side by side in the focal plane ofthe telescope. Only one thermopile was exposed to the Moon; the other saw only sky. This compensation technique is replaced today by the ac equivalent of chopping between the object and the sky. Lord Rosse compared his lunar deflections with those from blackened cans containing water of different temperatures, and he made extinction measurements at different elevations ofthe Moon. From these he derived a temperature ofthe full Moon of 400°-500° F, presumably by linear extrapolation ofthe water-can deflections. His same measurements can now be interpreted with Stefan's law and they do give the correct temperature ofthe Moon (Sin ton 1958). He measured the lunation curve of the Moon, and he also observed a total eclipse. He noted that the infrared deflections from the Moon during the eclipse were closely proportional to the visible light, and he deduced that the Moon's surface cooled extremely rapidly. His apparatus was not sufficiently sensitive to

Book Review: Lord Rosse's Telescope: The Astronomy of Birr Castle

Book Review: Lord Rosse's Telescope: The Astronomy of Birr Castle

Sir Howard Grubb, Parsons and Company

As the purpose of this lecture is to present to you a general picture of the Company, I think it will be appropriate to tell you a little about the historical background before passing on to describe some of our activities. Many people have asked me how it is that the firm carries the name of two distinguished men, both Fellows of the Royal Society, and what the connexion is between them. Like many good things our origin is in Ireland, and we owe our existence to the extraordinary energy and vision of the late Sir Charles Parsons. Parsons as a young man was tutored by Sir Robert Ball, an astronomer who thus found an opportunity to guide a brilliant intellect and also to enjoy the use of the largest telescope in the world, built by Parsons’s father at Birr Castle. At this time the firm of Thomas Grubb was well established in Dublin making astronomical and other instruments; indeed, there are several complimentary references to Thomas Grubb in the papers published by Parsons’s father, the 3rd Earl of Rosse and President of the Royal Society from 1848 to 1854. The Rev. Dr Robinson who was associated with Lord Rosse in the telescope experiments, wrote in 1840, ‘But as Short, in a spirit unworthy of his talents, took care that his knowledge should die with himself and Herschel published nothing of the means to which his success was owing, the construction of a large reflector is still as much as ever a perilous adventure, in which each individual must grope his way. Accordingly, the London opticians themselves do not like to attempt a mirror even of nine inches diameter, and demand a price for it which shows the uncertainty and difficulty of its execution. In Ireland we are more fortunate, for a member of our Academy, Mr Grubb, finds no difficulty in making them of admirable quality up to this size, or even fifteen inches.’ Unfortunately, the considerations governing the price of mirrors in London over a hundred years ago still seem to hold good to a considerable extent to-day, in Newcastle at any rate; and perhaps if Dr Robinson had witnessed the manufacture of the 4 ft. Melbourne speculum by Howard Grubb a few years later, the spectacle of the whole workshop roof in flames would have tempered his remarks about the immunity from hazard enjoyed in Ireland. In addition to carrying on his instrument business, Thomas Grubb was engineer to the Bank of Ireland, for which he made the banknote engraving and printing machines; on his retirement his son Howard carried on the instrument business, receiving his knighthood in 1887, and after valuable service to the Admiralty in the First World War, he moved the works to St Albans in 1918. Shortly after this, when Grubb was an old man, and his business was in difficulties, the inherited interest of Sir Charles Parsons in optics and astronomy led him to purchase the business of Sir Howard Grubb, thus to preserve for Britain the prestige and the experience of the best-established astronomical instrument makers in the world. In 1925, Parsons established a works alongside his existing turbine works in Newcastle upon Tyne, creating a self-contained organization under the name of Sir Howard Grubb, Parsons and Co. This factory, though it has grown a good deal in the last twenty years, is still quite a small affair; we employ altogether about 150 people and have our own drawing offices, design offices, laboratories and workshops. Grubb Parsons is a wholly owned subsidiary of C. A. Parsons and Co. Ltd, who specialize in the design and manufacture of very heavy electrical equipment for which large and accurate machine tools are essential. Thus Grubb Parsons have available to them not only their own workshops, but the large and heavy equipment of their parent company.

The Earl of Rosse (1840–1908)

AMONG the noblemen who during the nineteenth century devoted themselves to scientific pursuits, few were better known than the third and fourth Earls of Rosse. The former constructed the famous reflecting telescope at Birr Castle, King's Co., Ireland, and from 1848 until 1854 was president of the Royal Society, while the latter carried on his father's observations on nebulæ, made investigations on the heat radiated from the moon and held important offices in Ireland. Sir Laurence Parsons, the fourth Earl, was born at Birr Castle on November 17, a century ago, and was the eldest of six sons, of whom the youngest was Sir Charles Parsons, of steam turbine fame. Educated partly at home, he graduated from Trinity College, Dublin, at the age of twenty-four, and three years later, on his father's death, succeeded to the title and estates. From early manhood he took a part in public life, and in 1885 was made chancellor of the University of Dublin; in 1887 he became president of the Royal Dublin Society and in 1895 president of the Royal Irish Academy. He was a fellow of the Royal Society and of the Royal Astronomical Society from 1867.

The Late Earl of Rosse

THE Earl of Rosse, whose death on August 29 has been already announced, inherited a name of great renown in science. It was during his childhood that his father, the third Earl, erected the mighty reflecting telescopes at his seat at Birr Castle by which the name of Lord Rosse became famous throughout the world. The third Earl was endowed by Nature with much mechanical skill, and as a means of utilising his tastes and opportunities in the best possible manner for the advancement of knowledge he commenced to make reflecting telescopes. Every detail of the work was carried out in the workshops which gradually grew about Birr Castle. Incessant experiments were made to improve the methods of casting, grinding, and polishing the specula, until at last his efforts culminated in the mighty six-foot reflector which even at this day, notwithstanding the advances of the last sixty years, has still the greatest aperture of any astronomical instrument in the world.

Observations of Nova Persei made at Birr Castle Observatory, Parsonstown

Observations of Nova Persei made at Birr Castle Observatory, Parsonstown

The Milky Way from the North Pole to 10° of South Declination, drawn at the Earl of Rosse's Observatory at Birr Castle

DR. OTTO BOEDDICKER devoted the clear moonless nights for five years, from October 1884 to October 1889, to delineating the Milky Way as it appeared to his unaided eyes at Parsonstown, Ireland. His drawings were deposited in the library of the Royal Astronomical Society, and a note accompanying them was read at the meeting of the Society in November 1889. The work now before us consists of four excellent lithographic reproductions of these drawings, a brief introductory preface being added by Dr. Boeddicker. The Milky Way from the North Pole to 10° of South Declination, drawn at the Earl of Rosse's Observatory at Birr Castle. By Otto Boeddicker. (London: Longmans, Green, and Co., 1892.)

The Earl of Rosse's Great Reflecting Telescopes at Birr Castle

The Earl of Rosse's Great Reflecting Telescopes at Birr Castle

Our Astronomical Column

MEASUREMENTS OF LUNAR RADIANT HEAT.—Numerous measurements of lunar radiant heat have been made at Birr Castle Observatory by Lord Rosse and Dr. Copeland, and the results obtained have been published from time to time. During the total lunar eclipse of October 4, 1884, Dr. Otto Boeddicker, Lord Rose's present assistant, carried out a series of observations for the purpose of testing the striking result previously arrived at by Dr. Copeland, viz., that “the maximum of heat seemed to occur somewhat before full moon.” It was then found that “The heat as before diminished, and increased again nearly proportionally to the light, becoming inappreciable on reaching the limits of totality. The minimum of heat apparently fell later than that of illumination. But the most remarkable thing was that while during the short interval between the first contact with the penumbra and the commencement of total phase, all appreciable radiation vanished, between the end of total phase and the last contact with the penumbra, and even forty minutes later, the heat had not returned to the standard for full moon, being deficient by about 12 per cent.” These facts are remarked upon by Lord Rosse in an introduction to a paper by Dr. Boeddicker, giving the results obtained during the lunar eclipse of January 28, 1888 (Transactions of the Royal Dublin Society, Series III., vol. iv., Part ix., 1891). The measurements of radiation were commenced about an hour before the first contact with the penumbra, and a decrease of heat seems even then to have set in. But excluding this diminution of heat exhibited by the curve connecting the observations, there is indisputable evidence that the decrease had definitely commenced about three minutes before the eclipse began, and probably fifteen minutes before. This indicates, therefore, that the terrestrial atmosphere extends to a height of not less than 190 miles, and intercepts the sun's rays before any part of the moon has entered the earth's shadow. In 1888, as in 1884, the anomaly of the heat not returning to its standard value even I hour 40 minutes after the last contact with the penumbra, was observed. Dr. Boeddicker enumerates the series of observations required to elucidate these interesting points, and hopes soon to publish some further results of his investigations.