The results of testing adaptive optics system with a correlation detector of image displacements are discussed. The adaptive optics system consists of the following basic components: a tip-tilt mirror with piezoelectric drive, drive controller (RS-232 interface), computer (Pentium III, 550 MHz), DALSA video camera (256 x 256 pixel, 8 bit ADC, 203 frames/s), video camera controller (ISA bus), software (specially developed). The tests were conducted at the Big Solar Vacuum Telescope of the Institute of Solar-Terrestrial Physics (the Baikal Astrophysical Observatory). The adaptive optics system stabilized the position of a solar disk image fragment. The relative error of the control was, on the average, about 50%.