On Wesnedsay morning, people in various parts of the world will have the chance to witness an astronomical event that won’t be seen again until 2117 (that’s the year, not a quarter past nine!)
The transit of Venus will be best seen from east Asia and Australia. In Europe and parts of Africa it will begin before sunrise, and people in America can see it start before sunset on Tuesday. Unfortunately, in the UK we would only be able to see the final hour of the transit in the early hours of the morning, but it looks like it will be cloudy anyway. It begins at 22:09 GMT on 5 June and ends at 4:49 GMT on 6 June. If those times occur during daytime in your time zone, you can see it!
I have to give the usual warning. You must never look at the sun with the naked eye, or through a telescope, binoculars or camera. Doing so could cause sight loss. Either use special eclipse glasses, a camera or telescope with a proper solar filter, or project the image onto a screen. The TransitofVenus.org website has tips on viewing the transit safely, along with details of timings (it’s a bit US-biased; unfortunately the excellent transitofvenus.nl is down at the time of writing due to heavy traffic – they could have anticipated an increase in visitors for the next 24 hours!)
Transits of Venus always occur in pairs eight years apart, but those pairs are then separated by more than a century. In 2004, the transit occurred in the middle of the day in the UK, and it was a particularly hot, sunny day, unusually perfect for observing (the weather has a habit of spoiling any opportunities to see anything astronomical!) I was fortunate enough to be able to view this transit via the heliostat at the University of Leicester, from which these photos were taken. They still have a webpage about the 2004 transit with more images and animations.
If you are in a part of the world where the transit is visible, do take the opportunity to see a once-in-a-lifetime event if you can, although please remember the warnings about viewing it safely.