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Flag Staff and Time Ball

Permanent Exhibition

Sydney Observatory has two impressive timekeeping features that played significant roles in Sydney’s history.


The current flagstaff was installed in June 2008 and was generously provided by the Bruce and Joy Reid Foundation.

The flags currently flown are:

  • the Australian flag
  • the New South Wales flag
  • the Australian Aboriginal flag
  • the Torres Strait Islander flag
  • constellations visible during night sessions
  • planets visible in the night sky
  • phases of the Moon
  • maximum expected temperature for Sydney (three flags)
  • astronomical events including equinoxes, solstices, meteor showers and eclipses
  • various shipping signals

More than a century of shipping signals were sent and received using flags at the Sydney Observatory site.

Two flagpoles were used to pass messages to signal stations and port authorities between 1825 and the 1920s. Flags informed port authorities of the names, origin and cargo of new arrivals in Sydney Harbour. Weather and other information was communicated to ships in the harbour and neighbouring signal stations.

Time Ball

Today, the time ball on the Observatory’s tower is raised and dropped at 1pm every day to mark it’s historic purpose.

Before the Observatory was built, Sydney didn’t have an accurate time standard. The Observatory’s first function was to calculate the correct time from the movement of the stars. The time ball signalled the time to ships and the post office in Martin Place at 1pm each day, accompanied by a cannon blast to provide an audio as well as visual notification.

Read more about the time ball and its history in the MAAS online collection.

Donate today to conserve the Time Ball

When the Time Ball was installed atop Sydney Observatory in 1858, it allowed ships in Sydney Harbour to synchronise their chronometers in order to safely bring new passengers to Australia, to deliver mail to loved ones overseas and to plant the seeds for our growing nation.

Nearly 160 years later, the Time Ball continues to drop daily at 1pm, serving as a constant reminder of the technology that permeated our daily lives before the advent of radio, television or watches.

Now one of less than ten time balls in operation around the world, the Sydney Observatory Time Ball, like all heritage items, is in need of conservation.

With your gift, we can conserve the Time Ball to ensure it continues to operate for the next 160 years.

Donations over $2 are fully tax-deductible.

Plan Your Experience

All the information you need to plan your visit is available on the Sydney Observatory venue page, including:

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