Astronomical equipment, mural circle, brass /stone / glass, designed and made by Edward Troughton, London, England, 1807-1809, used at Parramatta Observatory, 1815-1825
There are two main types of telescopes. One uses a curved reflecting mirror to capture an image of celestial bodies the other uses a refracting lens to gather the light. This mural circle was used in conjunction with a telescope and was set into a wall. It was then turned on an axle so the telescope could observe the stars as they passed through their meridian.
These are the remaining parts of the mural circle which arrived in Australia with Governor Brisbane in late 1821. They and presumably the telescope were made by Edward Troughton, one of the most respected instrument makers of the day. It was used at Australias first permanent observatory situated at Parramatta. After the departure of Brisbane in 1825 and the dismissal of Charles Rumker in 1830 James Dunlop was appointed Government astronomer in 1831. Upon his return to Australia Dunlop found the equipment in a bad state of repair but nevertheless he commenced observations around the middle of January 1832 using the Troughton transit (H9891) and this mural instrument.
In 1835 a new transit telescope made by Jones was delivered to the observatory which replaced the Troughton transit. The Jones telescope however proved too difficult for Dunlop to manage on his own and instead he used the Troughton mural circle (H9893) for most of his observations.
One of the consequences of this was that Dunlop's observations for the 1835 'Catalogue of 7385 Stars', the first published catalogue of stars based on observations in Australia, proved full of inaccuracies. This mistake had serious ramifications for astronomy in Australia as local Governments and British scientists maintained a degree of skepticism about the value of investing in a new observatory. The instrument was put in storage after the Parramatta observatory was closed down in 1847 and remained so until the new Sydney Observatory was built above the Rocks.
The opening of the new observatory in 1858 saw many of the original Brisbane instruments taken out of storage. Given their age it is not surprising that the new Government Astronomer Rev. W.Scott felt this instrument was substandard. Perhaps as a result the instrument was little used by Scott but his successor H.C. Russell found little wrong with the instrument and in 1872 he used it to re-observe the southern star cluster Kappa Crucis.
This mural was also significant as it may have the prototype for one of Edward Troughton's early successes. Around 1807 he submitted an innovative design for a mural circle to Nevil Maskelyne the Astronomer Royal at Greenwich Observatory around 1807. In support of his design Troughton showed the board of visitors a two foot prototype of this circle which he had made for Sir Thomas MakDougall Brisbane. This is possibly the one which is now in the Powerhouse museum's collection. Its importance can be measured by the fact that the design was accepted by Greenwich Observatory and Troughton's mural circle set for the design standard for these instruments.
Unfortunately the telescope associated with this mural circle went missing sometime after being loaned to Sydney University in 1905. But even with its faults this instrument remains of national significance due to its pioneering role in Australian science and its association with Australia's earliest astronomers. It is also significant for its association withe early nineteenth century astronomical instruments and their makers.
H.C.Russsell, 'Report to the Observatory Board for 1872', cited in Lomb, N., 'The instruments from the Parramatta Observatory', in historical Records of Australian Science, 2004, 15
McConnell, A., Instrument Makers to the World; a History of Cooke, Troughton and Simms, William Sessions, York, England, 1992
Lomb, N., 'The instruments from the Parramatta Observatory', in historical Records of Australian Science, 2004, 15
Haynes, Raymond, Haynes, Roslynn, Malin, David, McGee, Richard, Explorers of the Southern Sky, Cambridge University Press, 1996
Australian Commonwealth Government, Historical records of Australia, Series 1, Governor's Dispatches to and from England, Volume 25, April 1846 - September 1847, Library Committee of the Commonwealth parliament, 1925
Australian Commonwealth Government, Historical records of Australia, Series 1, Governor's Dispatches to and from England, Volume 17, 1833- June 1835, Library Committee of the Commonwealth parliament, 1925
Forwarded to H. M. Secretary of State by Despatch, No. 141, 1847, Federation and Meteorology, http://www.austehc.unimelb.edu.au/fam/1541.html
Richardson, W., Catalogue of 7385 Stars, Chiefly in the Southern Hemisphere, prepared from observations made in 1822, 1823, 1824, 1825 and 1826, at the Observatory at Paramatta, New South Wales, Printed by William Clowes and Sons, For His Majesty's Stationary Office, 1835
Geoff Barker, August 2007
The mural circle was invented by Edward Troughton and made between 1815 and 1825 by Edward Troughton of London, England.
Cooke Troughton & Simms
In 1782 John Troughton purchased Benjamin Cole's shop in Fleet Street, London enabling him to sell his own signed products. His instrument making business supported several dynasties of Troughtons before becoming Troughton and Simms and later still Cooke Troughton & Simms. This firm was one of the most well respected firms of instrument makers of the 1800s.
While his brother enjoyed some early success, the business really expanded once Edward Troughton (1756-1835) took over the business in 1807. Edward and his brother John were both designers and manufacturers of instruments and the quality of their work won them contracts with the leading Government bodies of the time. These included The Royal Society, the Greenwich Royal Observatory, the Board of Longitude, the Board of Ordinance and the East India Company.
One of the main factors in the success of the business was the use of a dividing engine which could speed up the labourious process of marking the small divisions of measurement necessary for scientific instruments. This machine was based on that designed by Jesse Ramsden (1735-1800) which had won a prize from the British Board of Longitude in 1775. As a result of this the Board of Longitude was allowed to instruct Ramsden to allow up to ten other instrument makers to copy his machine. One of these was John Troughton and the new machines established both Ramsden's and Troughton's reputations. The dividing engine speeded up both accuracy and production and rather than spending 12 weeks, six days a week and eight hours a day graduating two meridian circles this machine enabled the same job to be completed in around 10 hours.
The workshop produced a broad range of instruments from large telescopes and theodolites through to smaller mathematical instruments. Before 1835 most of the optics appear to have been supplied by Dollond as Edward Troughton was reputed to be colour blind. It is also important to note that from the early years the precision engineering of castings and turnings of their instruments were mainly outsourced to Maudslay Field & Donkin or Ransome's & May.
One of Edward Troughton's apprentices, William Simms, was taken into partnership in 1826 and after Edward died in 1835, Simms became the manager of the establishment and the company became Troughton & Simms. Under Simms the company continued to expand and produced instruments for Britain and her colonies as well as for markets in Europe and America. When William Simms died in 1860 the estate was worth around £80,000. The company was next managed by William Simms (junior) and his cousin James who carried the firm into the industrial age.
During the 1860s they moved the company from Fleet St to two acres of land at Charlton on Woolwich Road and by 1866 the factory employed 61 men and 20 boys. For the 1874 transit of Venus, Troughton & Simms made only five transits and four portable azimuths but did refurbish some older telescopes loaned for the occasion. Telescopes and transits of the period were often hybrids with the structure ordered from Grubb's or Troughton & Simms with lenses from Cooke.
However by 1887 the company was able to produce all the parts necessary for their instrument and the company employed nearly 200 people. James Simms died in 1915 and the company was turned into a limited liability company by his two sons William and James. Things however were not so easy for the two sons and in 1922 the business was bought out by their rival T. Cooke & Sons becoming Cooke, Troughton & Simms.