William Parsons, 3rd Earl of Rosse KP (17 June 1800 – 31 October 1867) built several telescopes including the world's largest telescope in 1845 and it remained the world's largest for the rest of the century. Using this telescope he saw and cataloged a large number of galaxies. His 72-inch (6 feet/1.8 m) Leviathan was the first to see the spiral structure of what was later known as the
Whirlpool Galaxy, then called M51.
[http://amazing-space.stsci.edu/resources/explorations//groundup/lesson/scopes/rosse/index.php ]Life
He was born in
York in
Yorkshire,
England. He was educated at
Trinity College, Dublin, and
Magdalen College, Oxford, graduating with first-class honors in mathematics in 1822. He inherited an
earldom and a large estate in
King's County (now County Offaly) in Ireland when
his father died in 1841.
Rosse married
Mary Field, daughter of John Wilmer Field, on 14 April 1836. They had four children:
- Reverend Randal Parsons (26 April 1848 – 15 November 1936)
- Hon. Richard Clere Parsons (21 February 1851 – 26 January 1923), apparently made a name for himself building railways in South America.
In addition to his astronomical pursuits, Rosse served as an
Member of Parliament (MP) for
King's County from 1821 to 1834, an
Irish representative peer after 1845, president of the
Royal Society (1848–1854), and chancellor of
Trinity College, Dublin (1862–1867).
Scientific studies
In the 1840s, he built the
Leviathan of Parsonstown, a 72-inch (183-cm) telescope at
Birr Castle,
Parsonstown, County Offaly. He had to invent many of the techniques he used in constructing this telescope, both because its size was without precedent and because earlier telescope builders had guarded their secrets or had simply failed to publish their methods. Rosse's telescope was considered a marvelous technical and architectural achievement, and images of it were circulated widely within the British commonwealth. Building of the telescope began in 1845 and in 1847 it was put into service. The telescope replaced a that he had built previously.
Lord Rosse carried out pioneering astronomical studies and discovered the spiral nature of some
nebulas, today known to be spiral
galaxies. The first spiral galaxy he detected was
M51, and his drawings of it closely resemble modern photographs (today it is known as the
Whirlpool Galaxy).
Rosse named the
Crab Nebula, based on an earlier drawing made with his older 36-inch (91 cm) telescope in which it resembled a crab. A few years later, when the 72-inch (183 cm) telescope was in service, he produced an improved drawing of considerably different appearance, but the original name stuck.
William Parsons
A main component of Rosse's nebular research was attempting to resolve the
nebular hypothesis, which posited that planets and stars were formed by
gravity acting on gaseous nebulae. Rosse himself did not believe that nebulas were truly gaseous, but rather that they were made of such an amount of fine stars that most telescopes could not resolve them individually (that is, he considered nebulas to be stellar in nature). Rosse and his technicians claimed to resolve the
Orion nebula into its individual stars, which would have both political and cosmological implications, as at the time there was considerable debate over whether or not the universe was "evolved" (in a pre-Darwinian sense), a concept Rosse disagreed with strongly. Rosse's primary opponent in this was
John Herschel, who used his own instruments to claim that the Orion nebula was a "true" nebula, and discounted Rosse's instruments as flawed (an insult Rosse returned about Herschel's own). In the end, neither man (nor telescope) could establish sufficient scientific authority in its results to solve the question by themselves (the convincing evidence for the gaseous nature of the nebula would come later from
spectroscopic evidence, though it would not resolve the philosophical issues).
The largest telescope of the 19th century, the Leviathan of Parsonstown.
One of Rosse's telescope admirers was
Thomas Langlois Lefroy, a fellow Irish MP, who said, "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 Lord Rosse raised it single-handed off its resting place, and two men with ease raised it to any height."
Lord Rosse's son published his father's findings, including the discovery of 226 NGC objects in
Observations of Nebulae and Clusters of Stars Made With the Six-foot and Three-foot Reflectors at Birr Castle From the Year 1848 up to the Year 1878, Scientific Transactions of the Royal Dublin Society Vol. II, 1878.
Lord Rosse's telescopes
Lord Rosse built a variety of optical reflecting telescopes.
Rosse's telescopes used cast
speculum metal parabolically ground and polished.
- 36-inch (91 cm) (aka Rosse 3-foot telescope)
- 72-inch (180 cm) (aka Rosse 6-foot telescope or Leviathan), started in 1842 and completed in 1845
