Abstract: Method for compensating aberrations of an active optical system by a deformable mirror, comprising: (a) formation of a matrix N, binding the optical system aberrations with the displacements of the surface of a deformable mirror, presented as a superposition of natural frequency modes of a mirror simulator having the same geometric shape and the same elasticity characteristics as the deformable mirror but having zero density except for concentrated masses attached at points corresponding to the places of action of the force actuators onto the deformable mirror; (b) formation of the matrix M, binding the coefficients of the natural frequency modes of the mirror simulator with the forces or displacements of the force actuators that deform the mirror; (c) generation of the matrix of forces or displacements for loading the deformable mirror on the basis of the aberration measurement, using the matrices N and M.