A scanning system includes a cable take-up mechanism that uses a series of pulleys that determine the bend diameters of a scanning system. The mechanism is particularly suited for a spectrometric, e.g., infrared, scanning system where moving scanner or sensor head essentially houses only the optical elements while essentially of all the other electronic and optical components associated with the measurement are housed in an easily accessible compartment that is remote from the moving scanner head. Light is transmitted through optical fiber cables. The cable take-up mechanism maintains the fiber optic cable at essentially constant total bend length and bend diameter thereby minimizing any dynamic changes to spectral bend losses as the optical head is scanned. The light weight construction of the sensor head further reduces vibrations associated with the moving scanner head.