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 

作者机构：Astrophysics DepartmentNagoya UniversityNagoya464–8602Japan Graduate Institute of AstronomyNCUTaoyuan32001 Department of Physics and Institute of AstronomyNTHUHsinchu30013 

出 版 物：《Research in Astronomy and Astrophysics》 (天文和天体物理学研究（英文版）)

年 卷 期：2019年第19卷第9期

页      面：149-158页

核心收录：

学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学] 

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

主　　题：instrumentation:photometers instrumentation:polarimeters techniques:photometric techniques:polarimetric methods:observational ISM:magnetic fields 

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.