the Filter Wheel Assembly (FWA) – 8 positions, carrying 4 long pass filters for science, 2 broadband filters for target acquisition, one closed and one open position the Refocus Mechanism Assembly (RMA) – carrying 2 mirrors for instrument refocusing the Micro Shutter Assembly (MSA) – for multi-object spectroscopy but also carrying the fixed slits and IFU aperture the Grating Wheel Assembly (GWA) – 8 positions, carrying 6 gratings and one prism for science and one mirror for target acquisition