Observations

Time ball expert Roger inspects the time ball at Sydney Observatory

The view north from the Sydney Observatory time ball tower. Picture Roger Kinns
The view north from the Sydney Observatory time ball tower. Picture Roger Kinns

I visited Sydney Observatory on 9 June 2010 with Dr Catharine Abell, a Sydney friend who is willing to tolerate my enthusiasm for time signals. I live in Scotland, but I always enjoy visits to Australia for research and holidays. We were given a superb tour. Toner Stevenson showed us the principal exhibits, including an attractive presentation of how Aboriginal tribes interpreted the heavens, instruments that were used to study the 1874 Transit of Venus and the telescope domes themselves. Geoff Wyatt then showed us the time ball apparatus, one of the few surviving in the world from hundreds that existed in the nineteenth century. The team at Sydney certainly has infectious enthusiasm for the treasures at the Observatory. I would recommend a visit to anyone who is curious about astronomy and the measurement of longitude. You don’t have to be an expert, as the displays are all clear and helpful.

Sydney Observatory is special, not least because it has a fine time ball apparatus that was built by Maudslay, Sons & Field in London during 1855. It has been well looked after and is installed in rooms of generous proportions that make close inspection possible. The rack and pinion mechanism for hoisting the ball is similar in many respects to those built by Maudslays in 1853 for Deal in England and Edinburgh in Scotland, but there are significant changes in detail. Charles Todd, later to become famous for construction of the telegraph line from Adelaide to Darwin, records that he saw it being made at Maudslays’ works before he moved from Greenwich to Adelaide in 1855. It became operational in 1858 and is still in use over 150 years later. Henry Chamberlain Russell told Sir Charles Todd in 1899 how he had modified the apparatus during the 1870s, which gave some important clues for fresh study of the time ball at Lyttelton, NZ. We now know that the Lyttelton apparatus was made in 1873-4 using the 1855 Sydney design. New evidence shows that it was built by Maudslays for Siemens Brothers, who shipped it to New Zealand in 1874. You can go to Lyttelton to see what the Sydney apparatus was like before Russell modified it!

Dr Roger Kinns lives in Clynder, Scotland and is the author of the article “Time-keeping in the Antipodes: A critical comparison of the Sydney and Lyttlelton Time Balls”, Journal of Astronomical History and Heritage, 12(2), 97-107 (2009)

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