The Fan Observatory Bench Optical Spectrograph (FOBOS)

Abstract

ABSTRACTThe 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 Å<λ<6700 Å. Test data indicate that the instrument is stable and capable of measuring radial velocities with precision better than 3 km s−1 at a resolution of R∼1500 with minimal calibration overhead.