Thermal characteristics of the back-up structure for large aperture radio telescope

Large-aperture radio telescopes often experience degraded observational performance due to complex loading conditions in outdoor environments. A key factor affecting reflector surface accuracy is the non-uniform temperature distribution across the antenna back-up structure (BUS). Using historical temperature and environmental data from the Nanshan 26-m radio telescope, we applied Pearson correlation heatmaps, 3D DBSCAN clustering, and SHAP value analysis to identify the primary influencing factors. Results show that ambient temperature and solar incidence angle have the most significant impact on the thermal state of the BUS. Under extreme conditions, their combined effect can induce a temperature gradient of nearly 10°C across the structure. Furthermore, adjusting the relative solar angle is shown to effectively improve the thermal uniformity of the BUS. Field measurements confirm that this approach can restrict temperature variations across the structure to within ±1.5°C. The proposed method offers a valuable reference for thermal management of other radio telescope components.