On 8 June 2004, Venus will pass directly between Earth and the Sun. Local weather conditions permitting, this transit of Venus will be visible in its entirety over much of Europe and Asia, from London to Beijing. In London, the times of the first and last contacts will be 05c19c52 and 11c23c16 Universal Time, respectively-just over 6 hours from start to finish. In Sydney and Tokyo, only the ingress of the planet will be visible before sunset, and residents of Buenos Aries, Toronto, and New York will have to be up early to see the final contact. Another transit will occur on 6 June 2012, and then there will be no more transits until 11 December 2117 and 8 December 2125 <Maor, 2000>. Venus is nearly four times as large as the Moon. It is the nearest planet to Earth, but at its closest approach, it is still a hundred times more distant than the Moon, and its angular extent, as seen from Earth, is only about one-thirtieth that of the Moon. To the naked eye, the planet will appear as no more than a small black dot on the brilliant face of the Sun. Viewed through a telescope, the planet will be seen as a black disk, which will cover about 0.1% of the solar disk (Figure 1).