Sydney Observatory is a historic landmark and an astronomical observatory located in The Rocks area of Sydney, Australia. It was built in 1858, making it one of the oldest observatories in Australia. The observatory played a significant role in the development of timekeeping in Australia, and it continues to be an important centre for astronomical research and public outreach.

The observatory's main feature is its dome, which houses a 29 cm refracting telescope. This telescope was used to determine the time for ships arriving in Sydney Harbour, and it was also used to observe the Transit of Venus in 1874 and 1882. The observatory has other telescopes, including a 42 cm reflecting telescope, which is used for research purposes.

In addition to astronomical research, Sydney Observatory is a popular tourist attraction. The observatory offers guided tours, exhibitions, and interactive displays that explain the history of astronomy and the role of the observatory in Australian timekeeping. Visitors can also participate in stargazing events and view the night sky through telescopes.

Sydney Observatory is operated by the Museum of Applied Arts and Sciences, and it is open to the public every day except for Christmas Day and Boxing Day. It is located near many other tourist attractions in The Rocks, including the Museum of Contemporary Art and the Sydney Harbour Bridge, making it a popular stop for visitors to the city.