Multiple-Mirror Telescope Systems in Astronomy

The function of a telescope is to optimize the transfer of the information of interest from a source of finite angular size to the analytical device which is going to extract it. It is far from obvious that the conventional large telescope is the optimum fore-optical system for looking through a turbulent atmosphere. There are considerable scientific and financial advantages in going to multiple-imaging-elements and several groups in different parts of the world are working in this direction.