Establish a comparison of flatness standards for form/topography measuring instruments. This comparison will be the first one dealing with high-quality determination of form/topography of high-quality flats.
A high-quality flat artefact with a diameter of 330 mm, working diameter 300 mm, thickness of 70 mm, Zerodur, no coating, flatness RMS l/80 will be provided by the pilot laboratory.
Final Report 2016-07-04
The project has been completed and rusults are published esults published in an open access paper: Metrologia 54 (2017) 85–93 "Intercomparison of flatness measurements of an optical flat at apertures of up to 150 mm in diameter".