Mechanical design of the VIRUS2 instrument

VIRUS2 is a new NSF-funded facility instrument on the McDonald Observatory Harlan J Smith 2.7m Telescope. The instrument is a fiber-fed multiplexed integral field spectrograph consisting of 6 units, each with 4 spectral channels, to provide large on-sky area coverage coupled with broad spectral coverage. A novel beam switch module is implemented in the fiber feed which separates light into the pass bands of the four spectral channels. This paper details the mechanical design of the spectrograph, cryostat, and the beam switch module. A unique method for precise six degree of freedom positioning of the CCD detectors is presented, along with process for determination of required adjustments. Results from prototype testing and first article production is included.