A transit of Venus is coming. Only seven times since the invention of the telescope has Venus crossed the face of the Sun.

It’s a rare event because the orbit of Venus around the Sun is slightly inclined to Earth’s. So Venus appears to pass above or below the Sun’s disk. But periodically, when the Sun, Venus and Earth line up, Venus is in the plane of the Earth’s orbit and then you see Venus cross the Sun’s disk.

The transits occur in a regular pattern, every 8 years, 121.5 years, 8 years and 105.5 years. The last was in 2004, the next is in 2012 and the one after that in 2117.

In New Zealand we’re perfectly placed to see the next event. In Christchurch, Venus will be within the Sun’s disk between 10:33 and 16:25 on 6 June 2012. You can check out the timing at your location on this website.

Keep in mind you can’t just look at the Sun directly, or through a telescope! Putting it another way, never view the sun with the naked eye or with any optical device, such as binoculars or a telescope.