Multi-fiber coupling through a miniature lens system into the FOCES spectrograph

We present a new fiber-based light injection system for the high resolution spectrograph FOCES (Fiber Optics Cassegrain Echelle Spectrograph)1 which will soon start operating at the Wendelstein Observatory. The new system consists of several components such as a 4-fiber assembly (for simultaneous calibration), a new miniature lens system to reimage the light leaving the fibers onto the slit, as well as a new slit mask. The whole concept is specifically designed to provide high-accuracy, long-term stability for accurate radial velocity measurements and stellar atmosphere analyses.