TRISPEC: A Simultaneous Optical and Near‐Infrared Imager, Spectrograph, and Polarimeter

Abstract

We present the design, construction, and performance of TRISPEC (Triple Range Imager and Spectrograph), a simultaneous optical and near‐infrared imager, spectrograph, and polarimeter. This instrument splits the incoming light from a telescope into the three beams—one optical channel (0.45–0.90 μm) and two infrared channels (0.90–1.85 and 1.85–2.5 μm)—by means of two dichroic mirrors. It is capable of simultaneous three‐band imaging or spectroscopy, with or without polarimetry. Low‐resolution grisms (R∼70–360) cover a wide wavelength range of 0.46–2.5 μm, simultaneously. The instrument employs three arrays—one 512 × 512 SITe CCD and two 256 × 256 SBRC InSb arrays—to cover the three channels. It has been commissioned in the imaging, spectroscopic, and polarimetric modes on the United Kingdom Infrared Telescope, the University of Hawaii 2.2 m telescope, and the Okayama Astrophysical Observatory 1.88 m telescope since 1999 June.