Dutch open telescope: Status, results, prospects

The Dutch Open Telescope (DOT) on La Palma is a revolutionary telescope achieving high-resolution imaging of the solar surface. The DOT combines a pioneering open design at an excellent wind-swept site with image restoration through speckle interferometry. Its open principle is now followed in major solar-telescope projects elsewhere. In the past three years the DOT became the first solar telescope to regularly obtain 0.2″ resolution in extended image sequences, i.e., reaching the diffraction limit of its 45-cm primary mirror. Our aim for 2003-2005 is to turn the DOT into a 0.2″ tomographic mapper of the solar atmosphere with frequent partnership in international multi-telescope campaigns through student-serviced time allocation. After 2005 we aim to triple the DOT resolution to 0.07″ by increasing the aperture to 140 cm and to renew the speckle cameras and the speckle pipeline in order to increase the field size and sequence duration appreciably. These upgrades will maintain the DOT's niche as a tomographic high-resolution mapper in the era when GREGOR, Solar-B and SDO set the stage.