The Sydney Observatory has a long and important history of observing objects and events on Earth and in Space. But what does it mean to observe something? It means to watch something carefully or to take notice of something. That’s why we can find many instruments at the Sydney Observatory that were and still are used to observe phenomena in Space and on Earth.
To observe objects that are very far away, like planets, stars or comets, we use telescopes. The Sydney Observatory houses many of them. The Equatorial refracting telescope in the South Dome, for example, was installed to watch a rare astronomical event – the transit of Venus in 1885. That means Venus passes in front of the Sun, which happens less than two times in 100 years! This telescope is the oldest still working in Australia.
Observatories are also places to observe events on Earth, the weather for example. You can use rain gauges to measure how much rain has fallen at a certain location over a certain time or sunshine recorders to record the duration of bright sunshine during the day. Anemometers are used for measuring the force of wind.
The Observatory was built on a hill. It was the perfect location for ships to be able to see the time ball from Sydney Harbour and adjust their clocks. Sydney was becoming an important port in the 1850s for ships arriving from and departing to a variety of distant places. Telling the accurate time was only possible through a visual signal - the time ball dropping at 1 pm every day. It still drops at the same time very day.