On 13 May 1787, a fleet of 11 ships left England on a voyage to New South Wales. Given the navigation tools available and the small sizes of the convoy’s ships, Captain Arthur Phillip and his crew only managed to ensure their safe arrival because of the presence of navigators who were highly proficient in practical astronomy, particularly Lieutenant William Dawes. Britain’s fifth Astronomer Royal, Nevil Maskelyne, had convinced the Board of Longitude to supply Dawes with state-of-the-art instruments and allow the young Marine to establish a permanent astronomical observatory upon arrival. Dawes’ equipment included a portable tent observatory for use en route. From the mid-eighteenth century, voyages of exploration routinely carried tent observatories. Following James Cook’s deployment of a tent observatory on his first voyage to the Pacific (1768–1771), the design was altered by William Bayly for more convenient use on Cook’s second and third voyages. Bayly’s design became the standard structure of tent observatories assigned to shipboard astronomers. Following the First Fleet’s arrival in New Holland, between 1788 and 1791 Dawes established not one but two observatories within a kilometre of Sydney’s present-day centre. Today, a memorial plaque affixed to the Sydney Harbour Bridge serves as a reminder of Dawes’ efforts to build a functioning, permanent observatory. Unfortunately, the plaque indicates an incorrect location. Overwhelming contemporary evidence implies that Dawes’ Observatory was located on the northeastern tip of the promontory known as The Rocks, with any remains having vanished during the construction of the Sydney Harbour Bridge.

As Europeans explored and colonized south of the Equator, they brought with them familiar forms of sundials but were required to modify them to work in the Southern Hemisphere. The most obvious change to those familiar with Northern Hemisphere dials is the appearance of the hour lines and the shadow of the gnomon running backwards—e.g., going anticlockwise around the hour scale of a horizontal sundial and clockwise around the scale of a vertical dial. On closer inspection, one also recognizes that the polar-aligned gnomon points to the South Celestial Pole rather than the North Pole. This talk will show a number of examples of fixed and portable dials, including horizontal and vertical dials, equatorial dials, cannon dials, floating sundials, diptych dials, and universal ring dials that were made for southern latitude use.

Of special interest are portable dials designed for multiple latitudes and which contain lists of places and their locations. These gazetteers shed light on the relationship of time to religion, imperialism, and colonial administration in the Southern Hemisphere, and offer evidence of the dials being used by missionaries, explorers, soldiers, merchants, and governors. They also point to the transmission of cartographic and ethnographic knowledge during the colonial period.

Abstract: This presentation summarises the impact of the Commonwealth of Australia’s Constitutional ambiguities on Australian colonial astronomy between 1912 and 1945, focusing on Sydney Observatory's geodesy initiatives in 1916, 1923, and 1926. It examines the debates between state and Commonwealth governments regarding funding and oversight of observatories and whether these discussions had a greater impact on the development of astronomy than major historical events such as the World Wars and the Great Depression. The research draws on NSW State Archives and Records documents, emphasizing the Observatory's attempts at geographical triangulation and mapping the Pacific. By analysing the influence of political debates and policy decisions on the field, this talk aims to contribute to the understanding of Australian colonial astronomy and explore broader questions about the role of government funding and oversight in scientific research and development.