Whatever method you choose to observe this historical event, please be extremely cautious. NEVER look at the Sun with your naked eye or through ordinary sunglasses, and especially not through an unprotected telescope – this will cause permanent blindness. Instead, use one of these tried and tested methods:
For those with keen eyesight, the transit will be resolvable with a pair of ‘eclipse shades’, which have a special filter to permit safe, direct viewing of the Sun. However, subtle features such as the black drop effect will not be visible without magnification. Do NOT use these glasses to filter sunlight through a telescope eyepiece – the intensity will be too strong to protect your eyes.
Projecting a magnified view of the Sun through a telescope or binoculars onto a piece of white card (taking care to avoid overheating of the instrument optics by giving them a break every now and then) will provide a safe and satisfying view of the transit and will allow a group of people to admire the transit at the same time. Find out how to use pinhole projection with a pair of binoculars here.
It is also possible to project an unmagnified view of the Sun without the need for a telescope or binoculars, although finer details of the transit will not be resolvable. Find out how to build a simple pinhole projector here:
The transit is undoubtedly best viewed when magnified, either through a specially designed solar telescope or through a telescope fitted with a solar filter (although do not use filters that fit over the eyepiece – these can shatter under concentrated sunlight). Be sure to cap the finderscope, too; to safely find the Sun, orientate it such that the shadow of the telescope is at its smallest.
Many professional observatories around the world will be the streaming the event live across the Internet, providing an even safer way to share this once-in-a-lifetime event. ESA will be streaming the transit from both hemispheres of the planet: from Svalbard, Norway and from Canberra, Australia at the Venus Transit Monitor.