An infrared solar spectrum observed by ground-based telescopes is seriously affected by the background radiation both from the telescope and sky,relative to the visible wavelengths.Its accuracy is also influenced by t...An infrared solar spectrum observed by ground-based telescopes is seriously affected by the background radiation both from the telescope and sky,relative to the visible wavelengths.Its accuracy is also influenced by the spectral resolution of the Fourier transform spectrometer.In the paper,we developed a CO_(2)gas cell and installed it in the sample compartment to calibrate the spectral resolution of the Bruker IFS-125HR at infrared wavelengths.The measured spectral resolution is 0.00342±0.00086 cm^(-1)and 0.0059±0.00024 cm^(-1)at the wavenumbers of798 cm^(-1)and 2136 cm^(-1),respectively.We also updated a fully reflective sunlight feeding system to observe the solar spectrum near CO 4.66μm and Mg I 12.32μm.By quickly pointing the sunlight feeding system about1 degree away from the solar disk center,we are able to measure the background radiation from the telescope and the sky at Huairou Solar Observing Station.After removing the background radiation,our observed solar spectrum at CO 4.66μm is consistent with that from the National Solar Observatory.The Mg I 12.32μm working line selected by the Accurate Infrared Magnetic Field Measurements of the Sun(AIMS)project is also identified.Our method is helpful not only for the spectral resolution calibration and background radiation correction of AIMS but also for other infrared astronomical telescopes.展开更多
The Large Optical/infrared Telescope of China is a 12 meter diameter ground-based optical/infrared telescope which is proposed to be constructed in the western part of China in favor of its arid climate,and clear,dark...The Large Optical/infrared Telescope of China is a 12 meter diameter ground-based optical/infrared telescope which is proposed to be constructed in the western part of China in favor of its arid climate,and clear,dark nights.A site testing campaign was initiated between November 2016 and March2019 in order to investigate long term astronomical weather conditions in the western part of China,specifically,at three sites:Ali in Tibet,Daocheng in Sichuan and Muztagh-ata in Xinjiang.This is the first attempt to evaluate long term performances of three candidate sites with uniformly calibrated instruments and data collecting/processing methods for a two-year span in China.In this special issue,we present nine papers that describe the whole site testing campaign,including preparation,data collecting/processing methods,instrument set up at three candidate sites as well as detailed statistics for the measurement results from March 2017 to March 2019.展开更多
基金supported by the National Key R&D Program of China(2021YFA1600500)the Youth Innovation Promotion Association CAS(2023061)the National Natural Science Foundation of China(NSFC,Grant Nos.12003051,11427901)。
文摘An infrared solar spectrum observed by ground-based telescopes is seriously affected by the background radiation both from the telescope and sky,relative to the visible wavelengths.Its accuracy is also influenced by the spectral resolution of the Fourier transform spectrometer.In the paper,we developed a CO_(2)gas cell and installed it in the sample compartment to calibrate the spectral resolution of the Bruker IFS-125HR at infrared wavelengths.The measured spectral resolution is 0.00342±0.00086 cm^(-1)and 0.0059±0.00024 cm^(-1)at the wavenumbers of798 cm^(-1)and 2136 cm^(-1),respectively.We also updated a fully reflective sunlight feeding system to observe the solar spectrum near CO 4.66μm and Mg I 12.32μm.By quickly pointing the sunlight feeding system about1 degree away from the solar disk center,we are able to measure the background radiation from the telescope and the sky at Huairou Solar Observing Station.After removing the background radiation,our observed solar spectrum at CO 4.66μm is consistent with that from the National Solar Observatory.The Mg I 12.32μm working line selected by the Accurate Infrared Magnetic Field Measurements of the Sun(AIMS)project is also identified.Our method is helpful not only for the spectral resolution calibration and background radiation correction of AIMS but also for other infrared astronomical telescopes.
基金supported by the Center for Astronomical Mega-Science,Chinese Academy of Sciences(CAMS-CAS)supported by the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF)and administrated by the Chinese Academy of Sciences(CAS)supported by the National Natural Science Foundation of China(No.11873081)。
文摘The Large Optical/infrared Telescope of China is a 12 meter diameter ground-based optical/infrared telescope which is proposed to be constructed in the western part of China in favor of its arid climate,and clear,dark nights.A site testing campaign was initiated between November 2016 and March2019 in order to investigate long term astronomical weather conditions in the western part of China,specifically,at three sites:Ali in Tibet,Daocheng in Sichuan and Muztagh-ata in Xinjiang.This is the first attempt to evaluate long term performances of three candidate sites with uniformly calibrated instruments and data collecting/processing methods for a two-year span in China.In this special issue,we present nine papers that describe the whole site testing campaign,including preparation,data collecting/processing methods,instrument set up at three candidate sites as well as detailed statistics for the measurement results from March 2017 to March 2019.
