On the 8th of June in 2004 I had the chance to witness an event which takes place only every 243 years. A transition of the planet Venus exactly between Earth and Sun, which makes the Venus visible as a black spot on the disk of the Sun.

Additionally to living in the right time you also have to be at the right place, as such a transition in not visible on the whole world, but only in a part of it (like a solar eclipse). This transit was very good to observe all across Europe. The only variable left was the weather. But we were lucky! It was a mostly sunny day in Germany.

Around noon we left our office to observe the Sun. We used special glasses with a kind of aluminum foil to protect our eyes (left picture).

To make a photo from it we used a small telescope to project the sun onto a white piece of paper (right picture).

I also observed the Mercury transit in 2003, but it was less spectacular, because Mercury is so tiny. At the beginning we erroneously mistook a large sun-spot for the planet. :-)

More scientific information about this topic can be found here.