Daily Archives: November 27, 2011

The great Great Melbourne Telescope

When I hear the term ‘GMT’, I automatically think of Greenwich Mean Time.  Those of an astronomical bent, apparently, think of the Giant Magellan Telescope, four times more powerful than existing telescopes, and scheduled for completion in 2018.   But there’s another GMT too- The Great Melbourne Telescope, which I heard about at a lecture at La Trobe last week given by Richard Gillespie, the author of a recently-released book of the same title.  And a great little story it is too.

John Herschel, the son of the inventor William Herschel, first turned the telescope to the southern skies at the Cape of Good Hope in 1834-8, and in 1849 the British Association for the Advancement of Science called for a large reflecting telescope to be erected in the southern hemisphere.  Four years later they teamed with the Royal Society to create the Southern Telescope Committee to assess designs and seek funding.   The Cape of Good Hope, Sydney and Tasmania were considered as possible sites, but thanks to effective lobbying by William Parkinson Wilson of the University of Melbourne and support from the Victorian Government flush with post-Gold Rush wealth, the telescope was placed in Melbourne.  It was not the largest telescope in the world- that honour went to Lord Rosse’s ‘Leviathan of Parsontown’ in Ireland until 1917 but it was the second largest telescope at the time, and more importantly it was the largest steerable equatorial telescope, scanning not just up and down but across the skies as well.

It was the pride of Melbourne- and why shouldn’t it be.  The Irish-built telescope opened in a purpose built house in the grounds adjacent to the Botanic Gardens in June 1869. Its close proximity to Government House meant that the governor and visiting dignitaries and their ladies could pop in for a squizz (literally).  A brilliant image of the moon captured by the camera attached to the telescope in the 1870s was distributed to schools, libraries and Mechanics’ Institutes  throughout Victoria.  The “Great Melbourne” referred not only to the telescope, but to the self-image of Melbourne itself at the time as a centre of learning and civilization in an international context.

But technology and invention does not stand still, and other telescopes were devised with superior design and capacities surpassed the GMT.  Its lens became tarnished and by the 1940s the telescope was dismantled and moved to Mt Stromlo Observatory where it formed the skeleton of a new improved telescope, overlaid with new technology and materials.  This updating was an ongoing process and more than half of the original telescope was harvested in 1984 by Museum Victoria as a historical artefact.  The GMT was barely recognizable, visually at least, as the technology that had evoked such pride seventy years earlier.

In 2003 the Mt Stromlo Observatory was destroyed by fire, including the cannabalized remnants of the GMT. But,- and here there’s a flush of parochial pride- the fire stripped away all the plastic and modern metal, leaving the original cast iron skeleton of the telescope. Alongside the parts that had been harvested earlier, 90% of the original telescope still exists in one form or another.

The original telescope house still exists on the grounds of the former Observatory side, now part of  the Botanic Gardens.  There are plans to restore the house and the telescope and make it available again to the public which involves a balancing act between restoration and the re-creation of a :century telescope.  They won’t, for example, be using a speculum lens again that caused so much grief and expense in the original telescope.  They’re trying to raise a million dollars- which seems chicken-feed in these corporation days- hence the publication of this book (which I assume will be available at Museum Victoria even though it doesn’t seem to be in the bookshop yet).