Triple Range Imager and POLarimeter(TRIPOL)——a compact and economical optical imaging polarimeter for small telescopes  

作　　者：Shuji Sato Po Chieh Huang Wen Ping Chen Takahiro Zenno Chakali Eswaraiah Bo He Su Shinsuke Abe Daisuke Kinoshita Jia Wei Wang 

机构地区：[1]Astrophysics Department,Nagoya University,Nagoya,464–8602,Japan [2]Graduate Institute of Astronomy,NCU,Taoyuan32001 [3]Department of Physics and Institute of Astronomy,NTHU,Hsinchu30013

出　　处：《Research in Astronomy and Astrophysics》2019年第9期149-158,共10页天文和天体物理学研究（英文版）

基　　金：supported by Grant-in-Aid for Science Research from the Ministry of Education, Culture, Sports and Technology of Japan

摘　　要：We report the design concept and performance of a compact, lightweight and economical imaging polarimeter, the Triple Range Imager and POLarimeter(TRIPOL), capable of simultaneous optical imagery and polarimetry. TRIPOL splits the beam in wavelengths from 400 to 830 nm into g′-, r′-and i′-bands with two dichroic mirrors, and measures polarization with an achromatic half-waveplate and a wire grid polarizer. The simultaneity makes TRIPOL a useful tool for small telescopes for the photometry and polarimetry of time variable and wavelength dependent phenomena. TRIPOL is designed for a Cassegrain telescope with an aperture of^1 m. This paper presents the engineering considerations of TRIPOL and compares the expected with observed performance. Using the Lulin 1-m telescope and 100 seconds of integration, the limiting magnitudes are g′~19.0 mag, r′~18.5 mag and i′~18.0 mag with a signal-to-noise ratio of 10, in agreement with design expectation. The instrumental polarization is measured to be^0.3% in the three bands. Two applications, one to the star-forming cloud IC 5146 and the other to the young variable GM Cep, are presented as demonstrations.We report the design concept and performance of a compact, lightweight and economical imaging polarimeter, the Triple Range Imager and POLarimeter(TRIPOL), capable of simultaneous optical imagery and polarimetry. TRIPOL splits the beam in wavelengths from 400 to 830 nm into g′-, r′-and i′-bands with two dichroic mirrors, and measures polarization with an achromatic half-waveplate and a wire grid polarizer. The simultaneity makes TRIPOL a useful tool for small telescopes for the photometry and polarimetry of time variable and wavelength dependent phenomena. TRIPOL is designed for a Cassegrain telescope with an aperture of^1 m. This paper presents the engineering considerations of TRIPOL and compares the expected with observed performance. Using the Lulin 1-m telescope and 100 seconds of integration, the limiting magnitudes are g′~19.0 mag, r′~18.5 mag and i′~18.0 mag with a signal-to-noise ratio of 10, in agreement with design expectation. The instrumental polarization is measured to be^0.3% in the three bands. Two applications, one to the star-forming cloud IC 5146 and the other to the young variable GM Cep, are presented as demonstrations.

关 键 词：instrumentation:photometers instrumentation:polarimeters techniques:photometric techniques:polarimetric methods:observational ISM:magnetic fields 

分 类 号：P111[天文地球—天文学]