ADAPTIVE OPTICAL-IMAGE COMPENSATION EXPERIMENTS ON STELLAR OBJECTS

The resolution of a large telescope is limited by Various kinds of dyn amic wavefront disturbance such as atmospheric turbulence. This has be en a problem since the invention of the telescope. An approach for sol ving the problem is provided by adaptive optical techniques. Compensat ing for stellar objects in real time is, however, very difficult, beca use only limited light energy can be used and the temporal-spatial cha racteristics of dynamic disturbances place very high demands on system specifications. This paper reports the first experiment of a 21-eleme nt adaptive optical system for stellar objects on the Yunnan Observato ry 1.2-m telescope and presents the improvements of the system for low -light-level stellar objects. The experimental results show that the a daptive optical system can work satisfactorily when the photon counts are as low as 93 per subaperture per integrating time. The experiments show that the effects of adaptive optics in reducing the divergence a nd wandering of the image spot, in improving resolution, and in increa sing image contrast are significant.