Analyzing the MUSE opto-mechanics serving as an optical bench in 3D space

The Multi Unit Spectroscopic Explorer MUSE is a second-generation VLT instrument. With its high multiplexing factor of twenty-four individual spectrographs, it requires rather complex opto-mechanics to split the field of 1x1 arcminute on the sky into twenty-four sub-fields and guide them along the central instrument structure to the feeding point of each spectrograph. The requirements on the underlying mechanical structure are quite demanding in terms of opto-mechanical stability under thermal loads and thermal mismatch, warping of its basement and excessive earthquake loads. In total seven individual load cases and combinations of them have been analyzed in extensive finite-element analyses (within Nastran) with subsequent optical analyses (within Zemax). These two types of analyses will be addressed here and their combined output will be set into relation with the requirements.