Low-cost solar adaptive optics in the infrared

We have developed a low-cost adaptive optics system for solar observations in the infrared between I and 28 pm with the 1.5-m McMath-Pierce solar telescope. The 37-actuator membrane mirror and a fast tip-tilt mirror are controlled by a PC running Linux RedHat 7.1 that analyzes images from a 256 by 256 pixel, I kHz frame rate CCD camera. The total hardware cost is less than $25,000, and the system provides diffraction-limited performance under median seeing conditions above 2.3 pm. The single Pentium III processor provides enough computing power to analyze the 200 subapertures of the Shack-Hartmann wavefront sensor in real time. We describe the hardware and software implementations and show results from the first tests at the telescope.