Shown mounted to the cass focus of the telescope, this instrument is really two instruments: a multi-object spectrograph along one axis, and a high resolution spectrograph along the other. The design invloved teams in Canada and France. My work included the SIS camera assembly, the articulated carrier (shown in photos below) and other hardware.
The assembly is about two and a half meters in length and weighs 1600 pounds. The diagram shows the central mirror slide, which selects the spectrograph of choice, the cassette wheels with grated-prisms and filters, the cameras at either end, and the structural components.
A specialized handling cart enables the instrument to be mounted to the telescope and facilitates component servicing.
Each camera assembly consists of a lens tube with optics, focus and shutter mechanics, indexing and stepper drives, and other related hardware.