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The Great Melbourne Telescope was the largest fully steerable telescope of the 19th century. Installed at the Melbourne Observatory in 1869, the telescope symbolised a transition for early Melbourne from a colonial outpost to a city of learning and science.
The telescope was relocated to Canberra in 1945, where it was heavily modified for modern astronomy, before recording the first observation of dark matter as a massive compact halo object (MACHO) in the 1990’s. The telescope was engulfed by the 2003 Canberra bushfires, significantly damaging many components.
The remaining parts of the telescope have now been returned to Melbourne. About 70 percent of the components of the original telescope have survived in a condition suitable for reuse.
The telescope is now being restored for a return to its original building at the former Melbourne Observatory site. The restoration work is on display at Scienceworks.
The restoration project is being coordinated by:
As the metropolis of the great nation of the south, [Melbourne] possesses means and appliances, wealth and energy, with which no place on this side of the equator can enter into competition… [The telescope] is a noble object, to which some portion of the apparently inexhaustible wealth of our gold-fields may be worthily devoted.Melbourne University Professor William Wilson, arguing in 1856 for the erection of a large reflecting telescope in Melbourne.
The decision to commission the Great Melbourne Telescope reflected the wealth and confidence of Melbourne and the colony of Victoria in the 1850s and 1860s.
In turn, the Great Melbourne Telescope came to represent Melbourne’s ‘greatness’ to its citizens. Engravings of the telescope appeared in newspapers and magazines in Britain, Europe and America, projecting Melbourne’s confidence abroad.
When a visiting journalist in the 1880s dubbed the city ‘Marvellous Melbourne’, the locals seized on the phrase.
Melbourne grew dramatically following the discovery of gold in 1851. Founded in 1835, it was still a small trading port and centre of a pastoral industry with a population of 20,000 in 1850. In just a decade, Melbourne’s population exploded to 125,000.
The growing colony of Victoria, newly separated from New South Wales, suddenly faced huge challenges to deal with law and order and public infrastructure. But it also benefited from gold revenues, customs duties on imported goods and the wealth brought by immigrants, many of them skilled artisans.
In a few heady years, a range of public works and cultural institutions were established. The year 1854 alone saw the first railway line, the telegraph, and the establishment of a university, public library and museum. In 1856 an elected parliament sat for the first time.
In 1856 construction workers at the university and parliament building sites downed tools and marched successfully for the introduction of an eight-hour working day. Melbourne would be the first city in the world to gain the eight-hour day as a widespread right.
Little wonder then that William Wilson, professor of mathematics at the new University of Melbourne, argued that some part of Melbourne’s golden wealth could be directed to a large telescope. It would take ten years before Wilson’s dream took shape; a contract was placed for the telescope in 1865.
A local community of scientists and scientific institutions had been established in Melbourne by the mid 1850s. Several government scientific officers were appointed: Alfred Selwyn as Government Geologist, Robert Ellery as Astronomer to the new Williamstown Observatory, Ferdinand von Mueller as Government Botanist, and William Blandowski as Government Zoologist.
Few in the local scientific community were professional scientists; most were doctors, engineers or educated pastoralists, pursuing their scientific interests as a passionate hobby. They gathered in the newly-established Philosophical Society of Victoria (1854), soon renamed the Royal Society of Victoria.
Melbourne and the goldfields attracted settlers who saw education and self-improvement as a key to their personal success and to building a civilised community. Science and technology were seen by many as a measure of the degree of civilisation that had been brought to an untamed land, and of the economic and social improvement that had been achieved in the colony in a few short decades.
The Great Melbourne Telescope, the Botanic Gardens, the Museum and the State Library became powerful symbols of those achievements, showing Melbourne’s ability to emulate the institutions of London and the Continent.
In 1880 this culminated in the Melbourne International Exhibition, its focal point the imposing Exhibition Building, where science, technology and the practical arts displaced religion in a building that echoed the cathedrals of Europe.
When the Board overseeing the Melbourne Observatory decided in 1867 to call the new instrument the ‘Great Melbourne Telescope’, they had their finger on Melbourne’s pulse. Melbourne saw itself as a young, great city, worthy of the largest telescope in the southern hemisphere and the second largest in the world.
A popular pastime in colonial Melbourne in the 1870s and 1880s was to visit Melbourne Observatory at night to observe the planets, moon and stars, preferably with the Great Melbourne Telescope. Sometimes the Governor would bring dinner guests over from the adjacent Government House.
Groups were able to book ahead to view the Great Melbourne Telescope on evenings when the moon prevented scientific use.
When a superb photograph was taken of the Moon in 1872, the government directed Melbourne Observatory to distribute copies to all Victorian schools, libraries and mechanics’ institutes.
The Great Melbourne Telescope (GMT) was built by Thomas Grubb of Dublin from 1866 to 1868 and erected at Melbourne Observatory in 1869. It was a reflecting telescope with a speculum (metal) mirror of 48 inches (1.2 metres) diameter. At the time it was the second largest telescope in the world and the largest in the southern hemisphere.
The design and construction was overseen by a committee of eminent British astronomers, which approved Thomas Grubb’s revolutionary design. Although incorporating many of Grubb’s earlier innovations, the telescope was on a larger scale than anything he had previously attempted. Grubb’s firm went on to make many of the major telescopes around the world in the second half of the 19th century.
The telescope was operated at Melbourne Observatory by a Great Melbourne Telescope Observer: Albert Le Sueur (1869-70), E. Farie MacGeorge (1870-72), Joseph Turner (1873-83), and Pietro Baracchi (1883-92); thereafter it was used rarely.
The astronomers had to painstakingly observe faint nebulae and distant galaxies, then produce pencil sketches of their observations. Repeated observations over many nights were needed to gain an accurate drawing.
The telescope was working near the limits of available technology. There were underlying difficulties with tarnishing of its mirrors, flexure in the primary mirror, and vibration due to wind.
The telescope was not well suited to the emerging astronomical techniques of photography and spectroscopy. It took some excellent photographs of the moon, and some early photos of nebulae, which required exposures of up to 40 minutes. But smaller refracting telescopes were better suited at the time to photographic work.
When Melbourne Observatory closed in 1945, the telescope was sold to the Commonwealth Observatory at Mount Stromlo, Canberra. At Mount Stromlo the telescope was given a new 50-inch glass mirror made by Grubb-Parsons, and became an integral part of Mt Stromlo’s work from 1961 into the 1970s.
In the 1990s the telescope was rebuilt with two large-scale digital cameras for the MACHO project, a search for evidence of dark matter. Our first ever glimpse of MAssive Compact Halo Objects was through the GMT. Then in January 2003 a bushfire swept across Mt Stromlo, its firestorm destroying the majority of the telescopes and buildings.
1834-1838
John Herschel conducts systematic observations of the southern nebulae from the Cape of Good Hope.
1845
Lord Rosse constructs a huge telescope with a 6-foot reflecting mirror on his estate in Ireland: the ‘Leviathan of Parsonstown’. He observes nebula M51, and resolves that is a spiral galaxy.
1849
The British Association for the Advancement of Science calls for a large reflecting telescope to be erected in the southern hemisphere.
1853
The Southern Telescope Committee assesses designs, but the British Government declines to fund the telescope, due to its commitments to the Crimean War.
Williamstown Observatory commences as Melbourne’s first astronomical observatory.
1856
William Wilson, Professor at Melbourne University, in a paper to the Philosophical Institute of Victoria, calls for a large reflecting telescope to be built in Melbourne, as part of a national observatory.
1861
Edward Sabine, President of the Royal Society of London, encourages Wilson to rally support in Victoria.
1862
Wilson, as Secretary of Board of Visitors to Melbourne Observatory, proposes a large telescope to Governor Henry Barkly. The Royal Society of London supports the idea and settles on the preferred design.
1863
Melbourne Observatory opens.
1865
The Victorian Government orders the telescope from Thomas Grubb, Dublin.
1866
Albert Le Sueur appointed GMT observer and commences training in England.
1868
Feb: The Royal Society Committee inspects the finished telescope, and approves it as a ‘Masterpiece of Engineering’.
Dec: The GMT arrives in Melbourne.
1869
July: GMT operational, making observations of nebulae, comet, Neptune.
1870
Paper read to Royal Society of London detailing observations of nebulae of Argo and Orion with GMT, and of great changes in the nebulae since observed by John Herschel.
Le Sueur resigns as GMT observer; Farie MacGeorge appointed new GMT observer.
1872
Photos of Moon taken with GMT, and sent to Britain. Copies circulated to Victorian schools, mechanics’ institutes and libraries.
MacGeorge publishes paper on nebulae observations; determines that GMT’s light gathering power is greater than John Herschel’s large reflecting telescope.
GMT now working very well, after initial problems.
1873
Joseph Turner replaces MacGeorge as GMT observer.
1874
Turner commences systematic comparison with John Herschel’s nebulae observations from the 1830s.
1883
First photos taken of Orion Nebula in southern hemisphere, with new dry-plates. Not successful with η Argus Nebula.
Photos of κ Crucis, η Argus and Orion Nebula sent to Royal Astronomical Society.
Pietro Baracchi replaces Turner as GMT observer.
1885
Publication of Observations of the Southern Nebulae made with the Great Melbourne Telescope from 1869 to 1885, Part 1.
1888
Use of GMT declines.
Experiments to repolish the large mirrors commence, and continue to 1890, when Mirror A is installed with a good figure and polish.
1890
Government Astronomer Robert Ellery considers placing a refracting telescope on the GMT mounting, indicating he considers the optics in the telescope are at the end of their useful life.
1892
Examination of southern nebulae suspended, due to reductions in staff during the 1890s Depression. Large number of drawings and observations by Baracchi awaiting publication.
Discretionary resources of Observatory directed to a new international project to photograph the whole of the night sky, using a new telescope.
1894
GMT used for sketches of Mars at its close approach to Earth.
1910
Halley’s Comet is photographed by a camera attached to the GMT for tracking.
1944
Melbourne Observatory closes. GMT sold to Commonwealth Government for erection at Mount Stromlo Observatory near Canberra.
1961
GMT rebuilt at Stromlo with a 50 inch (1.25 metre) Pyrex mirror and new controls. Telescope used for photoelectric photometry and infrared observations.
1973
GMT decommissioned when a major bearing fails.
1984
Discarded parts of GMT returned to Melbourne.
1992
GMT rebuilt for MACHO (Massive Astronomical Compact Halo Object) project to detect evidence of dark matter. Telescope provided with two detector mosaics; at the time these were the two largest electronic cameras in the world.
2003
Bushfires destroy the major telescopes and buildings at Mount Stromlo.
2008
Remaining parts of GMT recovered and returned to Melbourne.
2009
Disassembly of telescope and documenting of parts.
Melbourne Observatory was established in 1863 through the merging of Williamstown Observatory, which had been established in 1853 as an astronomical observatory, and the Flagstaff Observatory, which had been conducting magnetic and meteorological observations since 1858. Robert Ellery was appointed Government Astronomer, in charge of the Observatory’s combined functions of astronomy, timekeeping, geodetic surveying, magnetic research and meteorology.
Ellery would remain Government Astronomer until his retirement in 1895, and during this period he created one of the leading scientific institutions in Australia. By the mid 1880s there was a staff of about 11, including assistant astronomers, meteorologists and a mechanic and messenger.
Ellery and his staff covered a wide range of scientific activities, from pure research to practical science that was critical for the colony’s operations. This included fundamental mapping of the southern hemisphere stars, published as catalogues and distributed to astronomers around the world. Special astronomical events such as solar eclipses, transits of Mercury or Venus across the face of the sun, and comets resulted in special projects to compare observations of the phenomena with astronomers worldwide. With the arrival of the Great Melbourne Telescope in 1869, the Observatory began a detailed study of the southern nebulae to see if these had changed in their character since observations by Herschel in the early 19th century.
Meanwhile, the Observatory contributed to the practical operation of the colony. It provided standard Observatory time to ship’s captains, central city clocks and the railways. Telegraphic connection to weather stations throughout Victoria and the other colonies enabled the gathering of meteorological data; by 1881 it was providing weather maps and weather forecasts to the daily papers.
In 1890 the Observatory joined an international project to take photographs of the entire sky, and create maps and catalogues from the photographs. Melbourne Observatory was one of 18 observatories to join what was the largest scientific project undertaken in the 19th century. Teams of workers were engaged to measure the star photographs. This project would consume the energies of the Observatory (and many others) for the next 20 years, and the final Melbourne catalogue was not published until 1963.
Robert Ellery retired in 1895, and the 1890s Depression had hit both staffing levels and operating funds. The Observatory took years to regain a full complement of staff. In 1908 the Commonwealth Government took over responsibility for meteorology and some staff transferred to the Weather Bureau. Australian Federation in 1901 had also brought new responsibilities, as the checking of weights and measures, previously done by Customs, was transferred to the Observatory.
It was symbolic that the building to house the weights and measures would be tacked onto the Great Melbourne Telescope House, recognition that the telescope had ceased its useful scientific life.
While the Observatory continued to do important astronomical observations, mounted eclipse expeditions, and undertook some new projects in astronomy and physics, by the 1920s there was a sense it was being weighed down by its administrative burdens, and the long-drawn out battles to get sufficient funds to reduce and publish observations made decades before.
Astronomy, like meteorology, was specifically mentioned in the Constitution as a Commonwealth responsibility, and Melbourne Observatory, like its counterparts in Sydney and Adelaide, was never adequately funded after World War I. Appropriately it was Pietro Baracchi (the second Government Astronomer) and Joseph Baldwin (the third and last Government Astronomer) who undertook observations every month for a year in 1911-12 at Mount Stromlo, leading to the creation of the Commonwealth Solar Observatory in 1924, the first astronomical institution of the federal government.
Melbourne Observatory closed in 1944. The timekeeping responsibilities were taken over by the Postmaster-General’s Department, the Great Melbourne Telescope and observational records were sent to Mount Stromlo, and the weights and measures function continued at the observatory site. Some original instruments remained, to be operated by the Astronomical Society for Victoria for its members and the general public. Older equipment was transferred to Museum Victoria.
The Melbourne Observatory site is now part of the Royal Botanic Gardens Melbourne, which in partnership with the Astronomical Society of Victoria interprets the history of the site and offers public viewings through the remaining telescopes.
This fact sheet series provides information on the GMT historical background, technical details of the instrument and the efforts to reconstruct this magnificent telescope for use by the public.
The Great Melbourne Telescope was a revolutionary telescope design, and a triumph of mid-19th century engineering. Prior to the GMT, the large reflecting telescopes of astronomers such as William Herschel and Lord Rosse were unwieldy beasts, requiring manual handling and tracking by teams of labourers.
Thomas Grubb devised an equatorial mount for the telescope that required just one assistant in addition to the observer. The GMT also incorporated a mirror support system that could substantially control flexure of the massive mirror – this idea had been devised by Grubb for use on Rosse’s Leviathan. Rather than having the observer placed dangerously at the top of the tube, the GMT eyepiece conveniently remained in the vicinity of standing eye height.
Many of these features would influence telescope design for the remainder of the century and beyond. But the GMT had its limitations, and the speculum metal mirrors were a constant headache to the observers and maintainers.
The GMT was used primarily for the systematic revision of the southern nebulae, comparing observations with the GMT with those undertaken by John Herschel in the 1830s at the Cape of Good Hope. The observations suggested that some significant changes had taken place, but it was difficult for astronomers to be sure if the apparent changes were real or a function of different instruments and observers.
The GMT was also used for photography and spectroscopy. It allowed the first observation of the spectrum of an extragalactic nebula. Its photographs of the moon were some of the finest taken in world in the 1870s, and its photos of nebulae the first taken in the southern hemisphere.
Its greatest astronomical achievements awaited its removal to Mount Stromlo Observatory in the 1940s and rebuilding with a modern mirror in the late 1950s.
It is a Masterpiece of Engineering. Its movements are surprisingly smooth and steady; it can be moved to any portion of the sky, even if it has to be reversed from one side of its pier to the other, in less than a minute by two operators and with very little exertion.Royal Society of London Committee, Feb 1868
In conclusion, I freely express my opinion that the entire instrument is a great triumph of mechanical engineering and optical skill; and, with the advantages of efficient working and a fine atmosphere, I trust it will add something to our knowledge of the heavenly bodies.British Astronomer William Lassell, Feb 1868
As in all instruments of large aperture, atmospheric condition is all important in the use of this one, and only those who have had experience observing with such instruments can form an idea of how limited are the hours per year, even in a climate like that of this part of Australia, in which such large apertures show the full extent of their powers. On the average of ordinary fine nights, the performance of this telescope on a planet or a double star is disappointing—except perhaps in occasional glimpses—to one accustomed to observe with smaller apertures; but on really good nights it is quite different, and such occasions show the most delicate markings on Saturn, clear separation of discrete points in some of the resolvable nebulae, and a separation of close double stars, indicating an optical perfection which under other conditions was not apparent.Robert Ellery, Observations of the Southern Nebulae Made With the Great Melbourne Telescope, Melbourne, 1885
The GMT was primarily used to observe the southern hemisphere nebulae, to detect whether changes had occurred since they had been observed by John Herschel at the Cape of Good Hope in the 1830s.
Astronomers debated whether nebulae were gaseous clouds in space, or star clusters so distant that they simply appeared to be clouds. Sufficiently powerful telescopes could hopefully resolve the nebulae into separate stars, or reveal other significant changes. This approach was reinforced in 1845 when Lord Rosse used his 6-foot Leviathan to determine that nebula M51 was resolvable into a spiral galaxy.
The observations with the GMT suggested that changes had occurred in the nebulae, and this seemed to suggest that at least some of the nebulae were gaseous clouds rather than star clusters, which would not show such changes.
Reporting on the changes in Argo nebula, GMT Observer Albert Le Sueur reported:
It seems difficult to imagine any conditions of aperture, definition, or other disturbing causes which could produce a view at all approaching to that seen by Sir John Herschel. We have therefore evidence of much weight that enormous changes have taken place in this wonderful region.Albert Le Sueur, ‘On the Nebulae of Argo and Orion, and on the Spectrum of Jupiter,’ Proceedings of the Royal Society of London, 1869/70, v. 18
Summarising the early GMT observations, the Royal Astronomical Society concluded:
A systematic revision of all the smaller southern nebula, commencing with those figured in Sir John Herschel’s work, has been entered upon, and the results are already most remarkable as indicating striking changes in many of them since they were drawn by the late illustrious astronomer.Report of the Council of the Royal Astronomical Society, Feb 1875
But the GMT observations could never really be conclusive. Too much depended on the variability of the observer, the atmosphere, and the difficulty in recording observations as pencil sketches, to be sure whether the changes were real or only apparent. Robert Ellery also had great difficulty in finding a suitable printing technique to reproduce the drawings accurately, for dissemination to astronomers around the world.
From 1864, William Huggins in England had used a spectroscope to show that some nebulae had spectra consistent with being gaseous clouds, while others were clearly star clusters. The GMT was fitted with a spectroscope, and its observers undertook some of the earliest spectroscopic analyses of southern nebulae.
Photographic equipment for the GMT arrived in 1872, and an elevated stage was erected at the northern end of the GMT House, so that the telescope could be lowered and glass plates inserted near the end of the telescope tube.
Superb photos were taken of the Moon in 1872, and prints were sent immediately to British astronomers to show the GMT’s sharpness and powers. The Royal Astronomical Society in London proudly hung the photo in its meeting rooms.
The GMT was used to take the first photos of nebulae in the southern hemisphere, in February 1883. Successful photos were taken of the Great Nebula of Orion, with exposures of one to four minutes. Images of the η Argus Nebula were not obtained despite exposures of up to 40 minutes because the nebula mostly emits red light, which was not detected by the blue-sensitive photographic emulsions of the time.
Robert Ellery conceded, however, that these photos were more experimental than definitive:
The great obstacle to obtaining photographs of faint objects is the difficulty of keeping such a large telescope steady during a period necessary for the exposure of the plate, so that, when a sufficient exposure has been obtained, the stars are all considerably enlarged from the vibrations and small movements of the telescope in the interval. A certain amount of scientific interest attaches to these experiments, but the results do not yet promise to be of such value as to warrant diverting the telescope from the revision of the nebulae for the purpose.Robert Ellery, Report of the Government Astronomer, 1883
Photography could not yet replace the painstaking work of pencil sketches of observations.
After Melbourne Observatory closed in 1945, the GMT was sold for scrap metal value to the Commonwealth Government’s Mount Stromlo Observatory near Canberra. In the late 1950s a modern telescope was built, utilising parts of the original polar axis, central cube and declination axis. A new 50 inch diameter Pyrex mirror was commissioned from Grubb Parsons, the descendant firm of the original maker.
The 50 inch was used extensively from 1959 into the early 1970s, measuring the brightness of stars. The links to the original telescope remained, with one of the original speculum primary mirrors remaining on the wall of the dome.
In the early 1990s the telescope was rebuilt again, but retained the 50 inch mirror and equatorial mounting. The world’s biggest (at the time) CCD array was installed in 1992 – 8 panels each 2048 x 2048 pixels. Similar technology now lies behind all digital cameras.
In 1993 the telescope was used to derive the world’s first observations of MACHOs (massive astrophysical compact halo objects) – a form of ‘dark matter’. The MACHOs were detected through gravitational lensing, the bending of a star’s light by the gravity of a large astronomical object. In 2000, to look for trans-Neptunian objects, the telescope was completely automated.
The goal of the Great Melbourne Telescope project is to restore the telescope to working order so that it may be used for educational and public viewing.
In August 2008, the Astronomical Society of Victoria, Museum Victoria and Royal Botanic Gardens, Melbourne signed a memorandum of understanding to pursue the feasibility of restoring the Great Melbourne Telescope and reinstating it in its original building at the former Melbourne Observatory site, adjacent to the Botanic Gardens.
The project is overseen by:
The Great Melbourne Telescope was recovered from Mount Stromlo Observatory in two stages.
Museum Victoria recovered more than half of the telescope from Mount Stromlo in 1984; these parts included a primary mirror, half of the telescope tube, setting circles, counterweights, bearings, load reduction assemblies and parts and a grinding and polishing machine for the speculum mirrors. The polar and declination axis assembly, and north and south pier supports remained at Stromlo as part of the rebuilt 50 Inch Telescope.
The bushfire that swept across Mount Stromlo destroyed all the major telescopes and many of the buildings. In the case of the 50 Inch Telescope, the aluminium dome itself caught fire and melted onto the telescope. Temperatures reached an estimated 500ºC, shattering its Pyrex glass mirror. The steel struts were softened, causing parts of the structure to sag. Only the large iron castings from the Great Melbourne Telescope, bent metal and broken glass remained.
The Astronomical Society of Victoria (ASV) and Museum Victoria (MV) discussed the future of the 50 Inch with the Mount Stromlo Observatory, and in 2008 it was agreed that the remaining parts of the original Great Melbourne Telescope could be returned to Melbourne. This decision also had to be approved by the Commonwealth Government, as the 50 Inch Telescope was on the National Heritage Register as a significant part of Mount Stromlo’s history.
A recovery team made up of Mount Stromlo staff, MV and the ASV dismantled the telescope parts for transport in November 2008.
Restoring the telescope for educational and public viewing means that the team will need to balance conservation principles (maintaining the existing state of the telescope) with restoration (returning the telescope to working order using original parts). In addition, some elements may need to be replaced entirely, either because they are missing or their use would potentially damage the original part.
The restoration is being carried out in accordance with the principles outlined in the Australia ICOMOS Charter for Places of Cultural Significance, The Burra Charter, 2013.
The original house built for the Great Melbourne Telescope remains on the former Melbourne Observatory site and is managed by the Royal Botanic Gardens, Melbourne.
After the Melbourne Observatory closed in 1944, the Telescope House was taken over by the Victorian government’s Weights and Measures Branch. Several changes have been made to the building since 1944. The original bluestone telescope piers were removed, the photographic stage at the north end was dismantled, and other rooms and structures were added to the building.
The Telescope house is now being restored in preparation for a return of the Great Melbourne Telescope.
Phoenix is a series of newsletters, intended for everyone interested in the project, and especially the ASV volunteers. Each issue, which has been collated and edited by the ASV, describes some of the work recently done, and looks forward to the immediate future.
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