The thermal aberrations of a telescope-limbograph have been investigated. Calculations have been carried out for the case in which it operates in a cyclic regime: 30 min observation of the sun, 60 min break, number of cycles 12. It is shown that, when high-thermal-conductivity silicon carbide is used as the material for the mirrors, they exhibit virtually no significant temperature gradients or thermal strains. The maximum distortion of the mirror profile does not exceed about 10−5µm, and this is quite satisfactory for the Lambda/50 allowance. The thermomechanical structure of the design of the space complex makes it possible to provide stable, high image quality of the optics and other all-round characteristics of the optical receiver unit of the limbograph as a whole.
Kh. I. Abdusamatov and S. I. Khankov, "Calculating the thermal aberrations of a space-based solar telescope-limbograph," J. Opt. Technol. 73, 24-28 (2006)