The National Institute of Standards and Technology (NIST) Dimensional Metrology Group (DMG), based in Gaithersburg, MD, is seeking a camera-based Fizeau interferometer. This equipment will replace ageing systems used to calibrate the diameter of spheres. These sphere calibrations support reference objects for length and coordinate measuring machines used by NIST and its customers. The work serves U.S. manufacturing and other industries through NIST’s dimensional calibration services.