中国科学院南京天文光学技术研究所机构知识库

Dome A, in Antarctica, offers an exceptional site for ground-based infrared astronomy, with its extremely low atmospheric infrared background noise and excellent seeing conditions. However, deploying near-infrared telescopes in the harsh environment of Antarctica faces the critical challenge of frost accumulation on optical mirrors. While indium tin oxide heating films effectively defrost visible-band Antarctic astronomical telescopes, their thermal radiation at infrared wavelengths introduces significant stray light, severely degrading the signal-to-noise ratio for infrared observations. To address this limitation, we have designed a mechanical snow-removal system capable of efficiently clearing frost from sealing window surfaces at temperatures as low as –80°C. Aperture photometry of target sources, Canopus and HD 2151, revealed that after six days without intervention, floating snow extinction reduced target brightness by up to 3 magnitudes. Following mechanical defrosting, the source flux recovered to stable levels, with measured magnitudes showing rapid initial improvement followed by stabilization. Data analysis indicates that a frost removal strategy operating every 48 h, with each operation consisting of 4–6 cycles, enables efficient removal of frost and snow without introducing additional thermal noise. Future work will focus on optimizing the adaptive control algorithm and exploring novel low-temperature defrosting materials to extend the periods during which Antarctic infrared telescopes can operate unattended.