It was with great anticipation that the Science staff and budding astronomers among the students awaited the transit of Venus. This was only the sixth time this phenomenon has been observed in the history of humanity – and the last chance to see it until the year 2117!
The transit of Venus happens when Venus passes between the earth and the sun - like an eclipse of the sun by the moon except that Venus is far more distant than the moon so that the planet appears as a small dark disc against the sun. This phenomenon brought Captain Cook to the South Pacific - where he made a successful observation in Tahiti in 1769 before continuing to Australia. Observations of the transit from different parts of the globe allowed astronomers to calculate the distance from the earth to the sun, and the size of the solar system - using Cook’ s d-ta a French mathematician named Lalanne calculated the distance of the sun form earth to be 153 million km – within 5% of today’s accepted value!
Unfortunately the day turned out to be cloudy, but the occasional break allowed excited students to observe the transit through special eclipse glasses. These reduced the sun to a dull red disc, against which the dark disc of Venus was clearly visible, sometimes through swirling cloud, but occasionally very clearly.
The fact that the sun was only sometimes visible only served to heighten the experience. It was possible to view a perfectly clear magnified image on a smart board, beamed by NASA, but the excitement of students of all ages (and staff) when they saw the real thing showed that there is no substitute for first-hand experience.
Many thanks to Mr Lars Hansen for loaning us a telescope for the occasion, and to Mrs Julia Hansen and Will Hansen for delivering it and helping to set it up.