At the moment the planet Venus is a brilliant object in the east before dawn. It is a world much the same size as the Earth, but very different in many ways, with its fiercely hot surface, its dense, choking atmosphere and its clouds of corrosive acid. Maps of its surface have to be compiled by radar. In this programme, Patrick Moore and Dr Peter Cattermole describe how the new radar-carrying spacecraft Magellan, which reaches Venus this month, will continue this work.