The Fan Observatory Bench Optical Spectrograph (FOBOS)

The Fan Observatory Bench Optical Spectrograph (FOBOS) is intended for single-object optical spectroscopy at moderate resolution (R?1500-3000) using a fiber-fed, bench-mounted design to maintain stability. Whenever possible, the instrument uses off-the-shelf components to maintain a modest cost. FOBOS supports Galactic astronomy projects that require consistently well-measured (?5 km s?1) radial velocities for large numbers of broadly distributed and relatively bright (V?14) stars. The spectrograph provides wavelength coverage throughout the optical spectrum, although the instrument design was optimized for use in the range 4700 ?<?<6700 ?. Test data indicate that the instrument is stable and capable of measuring radial velocities with precision better than 3 km s?1at a resolution of R?1500 with minimal calibration overhead.