Venus is set to move across the face of the Sun as viewed from Earth in a more than six-and-a-half-hour transit, which starts just after 22.00 GMT on Tuesday.
The transit is a very rare astronomical phenomenon that will not be witnessed again until 2117.
Observers will position themselves in northwest America, the Pacific, and East Asia to catch the whole event.
METHOD 1: Cut two holes in card for binocular eye-pieces. Push card onto binoculars and fix with tape. Block one lens (with lens cap, for example). Holding binoculars at waist height, angle towards Sun – do not look through them. Move binoculars around until card shadow minimized on viewing surface (piece of white card best). During six-hour transit, move set-up to follow path of Sun across sky, for example by mounting it on tripod or chair.
METHOD 2: Take piece of stiff card and pierce with pin. Hold it up and, looking away from the Sun, adjust angle of card until shadow minimized. Pinhole will project image of Sun into middle of shadowed area. Place another piece of card under shadow and adjust distance to get best picture – more distance gives larger but fainter image. Hole must be clean and as small as possible.
WARNING: Never observe the Sun with the naked eye or telescope, camera or other optical device. Doing so will seriously damage eyesight and may lead to permanent blindness.