LAUSR

Abstract. To control the mirror seeing effect and the thermal deformation, the actively cooled primary mirror is utilized in a large ground-based solar telescope. Due to direct solar illumination and high reflectivity of the mirror surface coating, the traditional contact or noncontact temperature measuring methods of the mirror surface are not available. A noncontact temperature estimation method based on the analytical heat transfer model of actively cooled primary mirror of a solar telescope is proposed. The experimental validation has been carried out on the actively cooled honeycomb mirror with 600-mm diameter. When the temperature on the mirror surface fluctuates between 23.7 deg and 26 deg, the corresponding estimation error is not more than 0.4 deg. The experimental results validate the correctness and accuracy of the proposed method.