A multi-object double spectrograph for the Large Binocular Telescope

We are building a Multi-Object Double Spectrograph for the Large Binocular Telescope. The instrument is designed to have high throughput from 320 to 1000 nm, spectral resolutions of 1,000-10,000, and multi-object capability over a 6 arcminute field. The design incorporates a dichroic and splits the science beam into a blue and a red channel, each of which can illuminate an 8,192 pixel long detector (with 15 micron pixels) with good image quality. The highly modular design can hold up to three gratings and an imaging flat and a selection of filters in each channel, all of which are quickly accessible; this allows for substantial observing flexibility. Progress on the construction of the instrument and future plans will be described.