Correction of static optical errors in a segmented adaptive optical system

Adaptive optical systems are designed to compensate for wave-front errors caused by atmospheric turbulence. In addition, they may also correct for wave-front errors associated with fixed optical aberrations in the host telescope. In general, however, adaptive optical systems cannot sense wave-front errors caused by imperfections in their own internal optical components. Consequently, these fixed internal errors will remain uncorrected. The problem of fixed internal aberrations has been noted in a segmented adaptive optics system designed for solar astronomy. This problem has been eliminated by measurement of the fixed errors, off line, through the use of a simple adaptation of a Hartmann test. Results from a recent experiment demonstrating the correction of the errors are presented.