M2FS: the Michigan/Magellan Fiber System

We describe the Michigan/Magellan Fiber System (M2FS) under construction for use on the Magellan/Clay telescope. M2FS consists of four primary components including: (1) A fiber-fed double spectrograph (MSPec) in which each spectrograph is fed by 128 fibers (for a total multiplexing factor of 256) and each is optimized in to operate from 370- 950 nm; (2) A fiber mounting system (MFib) that supports the fibers and fiber plug plates at the telescope f/11 Nasmyth focal surface and organizes the fibers into ‘shoes’ that are used to place the fibers at the image surface of the MSpec spectrographs;, (3) A new wide-field corrector (WFC) that produces high-quality images over a 30 arcmin diameter field; (4) A unit (MCal) mounted near the telescope secondary that provides wavelength and continuum calibration and that supports a key component in a novel automated fiber identification system. We describe the opto-mechanical properties of M2FS, its modes of operation, and its anticipated performance, as well as potential upgrades including the development of a robotic fiber positioner and an atmospheric dispersion corrector. We describe how the M2FS design could serve as the basis of a powerful wide-field, massively multiplexed spectroscopic survey facility.