Performance analysis and strategy optimization of mechanical defrosting for an Antarctic near-infrared telescope using aperture photometry 后印本

摘要: 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.