Tuesday, 5 June 2012
The Transit of Venus 2012
Historically, the Transit of Venus has been used to help calculate the earth's distance from the Sun. This rare alignment is how we measured the size of our solar system. Captain James Cook observed the 1769 Transit on his ill-fated Tahiti voyage. Many explorers and astronomers have made great voyages to learn more about the planets through the Transit of Venus.
The transit will cross the edge of the Sun at about 10.15am and take 18 minutes to move completely on to the solar disc. The mid-point will be at 1.30pm and Venus will exit the disc at 4.25pm.
New Zealand's weather forecast is not looking good! With much rain and cloud forecast, the chance of having a clear view is very slim. Lets keep our fingers crossed.
NEVER VIEW THE SUN WITH THE NAKED EYE OR WITH ANY OPTICAL DEVICE SUCH AS BINOCULARS OR A TELESCOPE!
Have you ever taken a magnifying glass out into the sun and burnt leaves or paper? When the focused sunlight comes through the lens, it is refracted and concentrated to a small spot. In your eye, you have a lens just like that. If you look at the sun, your eye-lens will concentrate the sun's light and focus it to a very small spot on the back of your retina. This can cause permanent eye damage or blindness. There are no pain sensors back there so you won't even know it's happening!!
Even if our view is very brief, it is very important that we do not look directly at the sun. Special viewing glasses can be purchased from both the Carter Observatory and the Astronomical Society of NZ. You can also make yourself a simple pinhole projector (the exploratorium has a simple explanation), all you need is some white card and a pair of binoculars.