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 s...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.展开更多
基金supported by Grant-in-Aid for Science Research from the Ministry of Education,Culture,Sports and Technology of Japan
文摘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.
