The site of Sydney Observatory, now known as Observatory Hill, was previously known as Windmill Hill, Citadel Hill, Fort Phillip and Flagstaff Hill, describing its functions over time. All of these functions relied on its position at the highest point overlooking Sydney Harbour.
The current flagstaff on top of Observatory Hill, generously provided by the Bruce and Joy Reid Foundation, was installed in June 2008 to commemorate the history of the site as a signal communication point and as part of the celebrations of Sydney Observatory’s 150th anniversary.
Signal flagstaffs were first erected here on Fort Phillip’s walls about 1810, followed shortly after by a semaphore mast. During the 1850s these were replaced by two tall signal masts, which remained in use until the 1930s – more than a century of shipping signals sent and received from here.
A signal station was set up on the hill in 1825 to receive messages from the station at South Head about ships arriving in the harbour. Until the 1920s two flagpoles were used to pass messages to other signal stations and the port authorities. Signal flags on the hill announced the arrival of ships into Sydney Harbour. The flags also informed port authorities of the names, origin and cargo of new arrivals. Weather and other information was communicated by signal flags to ships in the harbour, and to other signal stations at Bedlam Point near Gladesville and then to Mays Hill above Parramatta.
The cottage next to the flagstaff was designed by colonial architect Mortimer Lewis and built in 1848 as a residence and store for the signal master and his family. The cottage was extended in 1859 to add storage and office space.