Builder of "The Leviathan of Parsonstown": Lord William Parsons, 3rd Earl of Rosse (1800-1867)




The “Leviathan of Parsonstown” was a sixty-foot giant, with an eye more than six feet across.  For most of the 19th century it had provided the most magnified view of the sky possible in that era, and attracted astronomers from all over the world to an otherwise sleepy Irish village.

William Parsons, the creator of the “Leviathan” was an individual who was quite different from many of the stereotypical images associated with the men and women who have made great scientific breakthroughs.  Although he was a talented mechanic and a diligent student, he was not a prodigy or a genius.  He began his university career at Trinity College, Dublin and then went on to earn first-class honors in mathematics at Magdalen College, Oxford in 1822.  If anything set him apart from his fellow students, it was not his abilities, but his innate curiosity and love of the learning process.   In addition to his scientific pursuits he had a great deal of interest in social questions and was a profound student of political economy.

Parsons’s decision to devote the focus of his attention to astronomy was a deliberate one.  No great progress in astronomy had been made since the discoveries of Frederick William Herschel, the great astronomer and telescope builder of the previous century.  William Parsons believed that new breakthroughs in astronomy would depend on a man who not only had vision, but also the time and the financial wherewithal to pursue that vision.  William Parsons, also known as Lord Oxmantown, was the eldest son of Sir Lawrence Parsons, 2nd Earl of Rosse, a distinguished member of the Irish Parliament and holder of one of the wealthiest estates in Great Britain or Ireland.   The wealth and leisure that he was born into would allow William Parsons to put his mechanical skills to the great scientific endeavor of building the world’s largest telescope.

Great scientific endeavors often isolate men of vision from the individuals and the community around them.  This was not the case with Parsons.  Lord Oxmantown’s curiosity led him to create bonds and friendships, not only with likeminded scientists, but also with people from nearly all walks of life.  A story that was often told about Lord Oxmantown during his life was that when he was being given a tour of a large mechanical works in the north of England, the owner of the works stated that he was in great need of a foreman, and hoped that his visitor would accept the position.  Lord Oxmantown gave the man his card and gently explained that he was not exactly the man for the job, but that he appreciated the compliment.  This interaction led to a pleasant dinner and was the start of a lasting friendship.

Like his intellectual predecessor Herschel, William Parsons had a female companion in his scientific pursuits who was of equal, if not greater ability than her male counterpart.   Herschel’s sister Caroline had both acted as his assistant and had independently discovered eight comets, three nebulae and improved formulae regarding the position of stars.  William Parsons, Lord Oxmantown, married Mary Field, the daughter of a wealthy estate-owner, in 1836 and without her assistance the “Leviathan” would never have become a reality.  Lady Oxmantown was an accomplished blacksmith, an extremely rare skill for an upper-class woman of the time.  She constructed most of the iron work used to support the giant telescope, and this project kept more than 500 men employed during the depths of the Great Famine that devastated Ireland from 1845 to 1847.  This mother of eleven children was also an innovator in photography.  She was one of the first photographers to use wax paper negatives.  Many of her photographs serve today as an important chronicle of the building of the “Leviathan”.

Construction of the “Leviathan” had begun in 1842, and by 1847 it was in service.  Despite the advancements that Lady Oxmantown and others were making in the field of photography during this period, any observations made with the giant telescope had to be sketched by the observer.  News of William Parson’s discovery of the nebula M51 (today known as the Whirlpool Galaxy) and observations of the Crab Nebula spread throughout the British Commonwealth.  Many of Parsons’s hand-drawn sketches are amazingly consistent with modern spectroscopic images.

The “Leviathan” was truly a mechanical marvel.  Another Irish Member of Parliament, Thomas Langlois Lefroy, is quoted as saying “The planet Jupiter, which through an ordinary glass is no larger than a good star, is seen twice as large as the moon appears to the naked eye . . . But the genius displayed in all the contrivances for wielding this mighty monster even surpasses the design and execution of it.  The telescope weighs sixteen tons, and yet (Parsons) raised it single-handed  (sic.) off its resting place, and two men with ease raised it to any height.”

At the death of his father, William Parsons was elevated to the title of Third Earl of Rosse.  For many years Lord Rosse filled with marked distinction the position of President of the Royal Society, the premiere institution of scientific discovery in Britain and Ireland.  Lord Rosse’s home, Birr Castle, hosted monumental exhibitions of optical skill and attracted throngs of visitors from all over the world.  Lord Rosse himself was always available to those who sought his assistance and advice, and endeared himself to all with whom he came in contact.  On one occasion, when an assistant dropped and broke a mirror on which the great man had spent several hours of personal labor, Lord Rosse shrugged his shoulders and said, “Accidents will happen.”

The “Leviathan” remained the largest telescope in the world until 1914, when a larger one was built in California.  By this time the monster telescope was virtually obsolete, and was allowed to fall into disrepair.  In the 1970’s a television program, book and lecture by the documentarian Patrick Moore revived interest in this 19th Century marvel.  Reconstruction work began in 1996, and as the original plans for the telescope had been lost, the reconstruction team relied heavily on contemporary photographs taken by Lady Rosse.  In 1999 a new mirror was installed in the reconstructed telescope, and the “Leviathan” again attracts curious observers from all over the world to this sleepy Irish town.



Lord William Parsons, 3rd Earl of Rosse was my 3rd cousin, 5 times removed
Adam Lowe Martin (son of) - Allen Lowe Martin - Margaret Persse (daughter of) - Edwin Theophilus Persse (son of) - Dudley Persse - Theophilus Blakeney Persse - Henry Stratford Persse - William Persse - Elizabeth Parsons (daughter of)- William Parsons (father of)- Sir Laurence Parsons, 3rd Baronet Parsons - Sir William Parsons, 4th Baronet Parsons - Lord Laurence Parsons, 2nd Earl of Rosse - Lord William Parsons, 3rd Earl of Rosse