Royal Observatory & history of astronomy
The Herschel family and the Royal 0bservatory
The 19th century saw huge changes in the nature of both professional and amateur astronomy. At the end of the 18th century the Observatory was working on the systematic production of data for navigators. Amateur astronomers, meanwhile were discovering planets, comets and nebulae. As the 19th century progressed and the Observatory began to broaden its interests beyond positional astronomy, the subjects studied by amateur and professional astronomers became increasingly similar.
The relationship between the Observatory and the Herschel family lasted over a century. When William Herschel first discovered the planet Uranus in 1781, it was 5th Astronomer Royal, Nevil Maskelyne, who confirmed that it was a planet rather than a comet. When William's sister, Caroline, discovered her first comet, Maskelyne wrote of the important role played by amateurs. Caroline in turn worked on updating Flamsteed's catalogue of stars, his Historia Coelestis Britannica. The relationship continued and strengthened in the next generation, as William's son John and 7th Astronomer Royal, George Biddell Airy corresponded on many scientific projects.
William and Caroline Herschel
During the 18th century, the role of the Royal Observatory was to produce tables to aid navigation. The work was routine and practical. Astronomical discoveries were left to amateurs such as the Herschels. William Herschel was originally a musician from Hanover but became interested in astronomy in 1773.
He made his first telescope and began a project that would continue for the rest of his life - systematically studying areas of the sky, counting double stars, nebulae and star clusters.
In 1781 he spotted what he thought might be a comet using a 7ft telescope. He immediately wrote to Nevil Maskelyne, then Astronomer Royal. The comet turned out to be the planet Uranus.
William Herschel was not only an amateur astronomer, he was also an instrument maker. In 1785 King George III gave William a grant of £2,000 to build a 40ft reflector telescope for William's own use (the remains of which are now on display at the Observatory, outside the South Building). William also sold instruments to the Royal Observatory and to amateur astronomers.
Caroline Herschel was rescued by William from a life of domestic servitude under her mother in Hanover. He brought her back with him to England as a singer and his housekeeper. Caroline followed her brother into astronomy, initially as William's assistant, noting measurements, grinding telescope mirrors, and carrying out calculations on astronomical data, on top of running the household.
In 1782 William gave her a small telescope and she began 'comet hunting'. In her sweeps of the sky she found nebulae, new clusters and a total of eight comets.
William Herschel's 40ft telescope
William finished building his 40ft Newtonian reflector telescope in 1789 with grants totalling £4000 from King George III. It was the largest, most powerful telescope in the world and attracted visitors from far and wide. With it, William discovered the sixth and seventh satellites of Saturn and was able to resolve some globular clusters into individual stars.
William Herschel's 7ft telescope
William made and sold a number of 7ft telescopes. He used his own 7ft telescope to discover the planet Uranus. He originally named it 'the Georgian planet' in honour of King George III, but it was decided to name it after Uranus, the mythological father of Saturn, to be consistent with the naming of the other planets. Saturn by this same reasoning had been named after the mythological father of Jupiter.
John Herschel
During the 19th century the gap between the astronomical interests of the professional and gentleman amateur was closing. John Herschel and 7th Astronomer Royal,George Biddell Airy were involved in many of the same academic societies and sometimes sat on the same committees. They frequently corresponded with each other on scientific matters including the establishment of a new magnetic and meteorological department at the Observatory and the organisation of eclipse expeditions.
John went to South Africa in the 1830s, where he made important contributions to our knowledge of the nebulae of the southern hemisphere. His work was not confined to astronomy, however, and earlier in his life he carried out pioneering work in early photographic techniques.
Airy was later in correspondence with John's son, Alexander, Professor of Physics at the University of Durham between 1871-86. Among the topics they discussed was the use of photography in astronomy.
The 20ft telescope at Feldhausen, 1834–38
William Herschel had begun a survey of 'exotic objects', such as nebulae and star clusters, in the Northern Hemisphere. John Herschel completed the survey by plotting similar objects in the Southern Hemisphere. To do this, in 1834 he took his family to Feldhausen near Capetown in South Africa. The 20ft telescope he used was built by father and son together.
John Herschel drew many of the astronomical phenomena he observed during his survey of the Southern Hemisphere in South Africa between 1834-8. He was one of the first astronomers to observe nebulae in any detail. The Orion nebula is the nearest bright nebula to Earth and can be seen with the naked eye.
