The measurement and calbration interferometers SP 15000 C with a measuring range of at least 15 m are designed for high-precision length, angle and straightness measurements on positioning axes. A synchronous, continuous 5 DOF-measurement is possible. The horizontal and vertical components of axis straightness are measured by a rotatable optics. The measuring refl ector is based on a combination of hollow refl ectors and a rotatable Wollaston prism. Other accessories are the straightness mirror and a 90° beam defl ection. Calibration software according to the currently applicable standards is available. The measuring and calibration processes can be synchronized with a position controller. Different triggering possibilities for acquisition of the measured values are available. The measured values are transferred to a computer via a fast USB interface. Optional interfaces are available.