Performance Analysis and Strategy Optimization of Mechanical Defrosting for the Antarctic Near-Infrared Telescope Based on Aperture Photometry

The Antarctic Dome A offers an exceptional site for ground-based infrared astronomy due to its extremely low atmospheric infrared background noise and excellent seeing conditions. However, deploying near-infrared telescopes in Antarctica's harsh environment presents a critical challenge: frost accumulation on optical mirrors. While indium tin oxide (ITO) heating films effectively defrost visible-band Antarctic Astronomical Telescopes, their thermal radiation in the infrared band introduces significant stray light at the optical pupil. This severely degrades the signalto-noise ratio for infrared observations. To address this limitation, we designed a mechanical snowremoval system capable of efficiently clearing frost from sealing window surfaces at temperatures as low as -80℃. Aperture photometry of target sources (e.g., 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 the measured magnitudes showing rapid initial improvement followed by stabilization. Data analysis demonstrates that clearing frost every 48 hours using 4 -6 cycles per operation restores window transmittance to 92% of its initial value without generating additional thermal noise. Future work will focus on optimising the adaptive control algorithm and exploring novel low-temperature defrosting materials to extend the unattended operation periods of infrared telescopes.