CISCO: Cooled Infrared Spectrograph and Camera for OHS on the Subaru Telescope

This paper describes a Cooled Infrared Spectrograph and Camera for OHS (CISCO), mounted on the Nasmyth focus of the Subaru telescope. It is primarily designed as a back-end camera of the OH-Airglow Suppressor (OHS), and is also used as an independent, general-purpose near-infrared camera/spectrograph. CISCO is based on a single 1024x1024 format HgCdTe HAWAII array detector, and is capable of either wide-field imaging of 1.8'x1.8' field-of-view or low-resolution spectroscopy from 0.9 to 2.4 um. The limiting magnitudes measured during test observations were found to be J=23.5mag and K'=22.4mag (imaging, 1" aperture, S/N=5, 1 hr exposure).