|SDO‘s Ultra-high Definition View of 2012 Venus Transit|
The last transit of Venus took place recently on 5 and 6 June 2012, and it was the last Venus transit of the 21st century. Venus transits are very rare events. The next one will be December 10–11, 2117. So it is much likely that this on was the very last Venus transit I had a chance to see in my lifetime.
A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and Earth and thus becomes visible against the solar disk as a small shadow. During a transit, Venus can be seen from Earth as a small black disk moving across the face of the Sun. The duration of such transits is usually measured in hours. By using a well suited dark filter Venus transits are visible even without telescopes. But beware of trying to watch a Venus transit with your naked eye, because it would damage your sight.
It is interesting to mention that the last Venus transit was only 8 years ago. Actually Venus transits follow a pairwise pattern that generally repeats every 243 years, with pairs of transits eight years apart separated by long gaps of mor than a century.
|Jeremiah Horrocks observing the transit of Venus
on 24th November 1639
Venus transits are historically of great scientific importance as they were used to gain the first realistic estimates of the size of the Solar System. The first modern observation of the Venus transit was by English astronomer Jeremiah Horrocks, who corrected Johannes Kepler’s calculation for the orbit of Venus and realized that transits of Venus would occur in pairs 8 years apart. Thus, he was able to predicted the transit in 1639 that he observed with the help of a small telescope to project the magnified image of the sun on a piece of paper. In combination with the principle of parallax Horrocks’ observations allowed him to make a well-informed guess as to the size of Venus, as well as to make an estimate of the distance between the Earth and the Sun that was more accurate than any other up to that time.
At yovisto you might watch a NASA video of the recent Venus transit from 6th June 2012.