The solar telescope GREGOR is under construction on the canary island Tenerife. A large effort was made to thermally
characterize the telescope during the design phase. The image quality is very sensitive to differences between ambient
and structure or main mirror temperatures. Tests with the GREGOR telescope structure and an integrated dummy mirror
were made to investigate the distribution and temporal behavior of the temperature of the telescope and main mirror.
R. Volkmer, R. Volkmer,
"Thermal characteristics of the solar telescope GREGOR", Proc. SPIE 7012, Ground-based and Airborne Telescopes II, 70120K (22 July 2008); doi: 10.1117/12.790326; https://doi.org/10.1117/12.790326