MCI: Multi-channel Imager on the Chinese Space Station Survey Telescope

Abstract The Multi-Channel Imager (MCI) is a powerful near-ultraviolet (NUV) and visible imager onboard the Chinese Space Station Survey Telescope (CSST). The MCI provides three imaging channels, which are the NUV channel, the Blue channel and the Red channel, with the wavelength ranges of 255–430 nm, 430–700 nm, and 700–1000 nm, respectively. MCI’s three channels can target the same field simultaneously, which is unique compared to other imagers onboard the Hubble Space Telescope (HST) or the James Webb Space Telescope (JWST). Each channel employs a CCD focal plane of 9216 × 9232 pixels and ∼7 . ′ 5 × 7 . ′ 5 field of view (FOV), which are ≳4 times the FOVs of HST imagers. The MCI’s three channels feature unprecedented sensitivities and FOVs, complementing the NUV and visible capabilities of the CSST for high-precision photometry and weak-signal detection, which would help build a new standard-star system and the deepest UV-Optical exposures for CSST. Rich filter sets of MCI would help explore other areas of science such as local emission line mapping, searching for high- z Ly α emitters, etc. Here we present key design features, results of current ground tests, and suggest observing strategies for the MCI.