On June 5th, 2012, Venus will pass across the face of the sun, producing a silhouette that no one alive today will likely see again. Transits of Venus are very rare, coming in pairs separated by more than a hundred years. This June's transit, the bookend of a 2004-2012 pair, won't be repeated until the year 2117. Fortunately, the event is widely visible. Observers on seven continents, even a sliver of Antarctica, will be in a position to see it.
The June 8, 2004, transit of Venus photographed by Frans Snik at the Dutch Open Telescope in La Palma, Canary Islands.
The nearly 7-hour transit begins at 3:09 pm Pacific Daylight Time (22:09 UT) on June 5th. The timing favors observers in the mid-Pacific where the sun is high overhead during the crossing. In the USA, the transit will at its best around sunset. That's good, too. Creative photographers will have a field day imaging the swollen red sun "punctured" by the circular disk of Venus.
This year’s transit is the second of an 8-year pair. Anticipation was high in June 2004 as Venus approached the sun. No one alive at the time had seen a Transit of Venus with their own eyes, and the hand-drawn sketches and grainy photos of previous centuries scarcely prepared them for what was about to happen. Modern solar telescopes captured unprecedented view of Venus’s atmosphere backlit by solar fire. They saw Venus transiting the sun’s ghostly corona, and gliding past magnetic filaments big enough to swallow the planet whole. One photographer even caught a spaceship, the International Space Station, transiting the sun alongside Venus.