2000NewA....5..223D

The Multi-Aperture Real Time Image Normalisation Instrument (MARTINI) is an adaptive optics system designed to operate at one of the Nasmyth focal stations of the 4.2 m William Herschel Telescope. Correction of atmospherically distorted images is achieved by the action of a six element segmented mirror in a real-time servo loop controlled by the signal from a CCD based Shack-Hartmann wavefront sensor. A unique aspect of the MARTINI instrument is that, from its conception, it was designed to be capable of image sharpening at visible wavelengths. An outline of the mechanical and electronic arrangement of MARTINI is given, together with a description of its modes of operation, facilities and performance. Also described are some of the first scientific results obtained with the instrument.