Transit of Venus 1874, a book
describing the observations of Sydney Observatory astronomers during the December
1874 transit. Collection of the Powerhouse Museum
Family viewing the Transit of Venus
at Sydney Observatory, June 2004
From 3 June 2004
On the afternoon of Tuesday 8 June 2004, the planet Venus crossed in front of the Sun. When Venus's dark silhouette moved across the disc of the Sun - a transit of Venus - we witnessed one of the rarest and most famous events in astronomy. This was the first transit of the planet in more than 120 years.
Transits of Venus were important in past centuries because they provided the opportunity to measure the distance of the Earth from the Sun and hence determine the scale of the solar system. It was Edmond Halley, of Halley's Comet fame, who pointed out the feasibility of using transits for this purpose.
The most celebrated transit, in June 1769, was observed from many places. One of the observers was Lieutenant James Cook who sailed to Tahiti with the astronomer Charles Green in the ship HMS Endeavour. After observing the transit, Cook opened sealed orders from the Admiralty to search for the unknown southern continent. He did not find this mythical land, but did claim New Zealand and New South Wales for the British Crown.
The 2004 transit
The June transit of Venus was seen in Europe, Asia and most of Africa. In those regions the transit was seen from beginning to end – from Venus appearing to enter the Sun's disc to it leaving the disc just over six hours later.
In Australia we saw the start of the transit, but everywhere on the continent the Sun set before the end of the event. We are more fortunate though than people in New Zealand where the Sun set before the beginning of the transit.
Powerhouse Publications
Transit of Venus: the scientific event that led Captain Cook to Australia
Available from the Powerhouse Museum Shop, Sydney Observatory and by mail order.
