OSIRIS is a near-infrared integral field spectrograph designed for the Keck Adaptive Optics System.

The instrument uses a lenslet array to sample a small rectangular patch of the sky at resolutions approaching the diffraction limit of the 10-meter Keck Telescope. OSIRIS will provide moderate spectral resolution (R~3800), and full broadband (z, J, H, and K) spectral coverage at over 1000 spatial locations in the AO-corrected field. The integral field design makes optimal use of new large-format (2048x2048) infrared arrays, and is well matched to the compact nature of AO targets.