Fulldome is a technology that enables an undistorted projection of moving images on a curved area, e.g. the 360°-screen of a planetarium. Up to the mid-1990ies, all-dome projections were stationary images provided by exactly adjusted slides. The fulldome technology affords dynamics over the whole dome using video projectors and a special computer software. Two formats are distinguished: the single and multi projector systems. As for the first, the projector is placed in the centre and displays the movie via a fish-eye lens. The advantage lies in the uniform illumination, such that no margins of images overlap. In the multiple system the picture is split into segments and distributed among the projectors. They permit a higher resolution. London was the first planetarium replacing the classical star projector against fulldome. The most modern facilities combine the opto-mechanical device with the fulldome technology.