This paper is a presentation of the so-called COME-ON adaptive optics prototype system developed jointly by four
European institutions. This system has been tested on the 1.52m telescope of the Observatoire de Haute Provence on
October 12 to 23 and November 13 to 24, 1989. Diffration-limited infrared imaging has been achieved during these first
tests. The adaptive optics system consists of a 19 actuator deformable mirror and a Hartmann-Shack type wavefront
sensor. In this instrument the wavefront sensing is performed at visible wavelengths while the correction is performed for
near infrared imaging (1 .2 to 5 .tm). Specialized computers drive the deformable mirror and a tip-tilt mirror. The
bandwidth of the servo-loop is 9 Hz at 0 dB point in open-loop. The results obtained with this instrument will be very
useful for the design of the future adaptive optics system for the ESO Very Large Telescope (VLT).