Performance Analysis and Strategy Optimization of Mechanical Defrosting for an Antarctic Near-Infrared Telescope using Aperture Photometry

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 hours, 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.