The weather has miraculously cleared for the viewing of the transit of Venus today (Wednesday 6 June 2012).
Venus' dark silhouette is passing visibly in front of the sun, a very special "transit" which will not occur again until December 2117.
UTAS is projecting the image of the sun from the heliostat (sun-tracking mirror) on top of the Physics Building. Crowds of interested stargazers, particularly children, are visiting the Physics building to see the transit and listen to lectures about the event.
Associate Professor Dr Simon Ellingsen, from the UTAS School of Physics said the transit was one of the rarest events in astronomy.
"A transit is where a planet passes between the Earth and the Sun, so Mercury and Venus are the only planets in our solar system where we can see a transit from the Earth.
"Transits are like an eclipse, but because the planets are much more distant than the Moon they only block a tiny fraction of the Sun."
Dr Ellingsen said transits are important historically.
"From a scientific perspective, the observations of the Transits of Venus which occurred in the 18th Century allowed the first accurate measurements of the scale of the solar system.
"The Transit of Venus was also the main aim of Cook's voyage to the South Pacific in 1769/70, his explorations of New Zealand and Australia were an additional secret mission," Dr Ellingsen said.
Safety note: Never look at the sun directly, especially not through any optical instrument. Even with a small pair of binoculars you can be quickly blinded.
For more information on the transit and how to view it safely, visit the Australian Astronomy webpage.
Image: Dr Simon Ellingsen giving a public talk on the history of the transit.