Components in the laboratory setup. Left: light from a 300 mW λ 532 nm laser is made chaotic by scattering from microscopic particles in a square-top cuvette and focused by a condenser onto artificial “stars”, which are mechanical apertures in a rotatable holder. Right: the “stars” are observed by a group of (here) five small telescopes with 25 mm apertures, each equipped with a photon-counting SPAD detector. One unit perpendicular to the others uses a 45-degree mirror to obtain a particularly short baseline. Another pair of two telescopes behind one beamsplitter serves to measure zero baseline, as required for calibrations. Two-dimensional coverage is achieved by successively rotating the position angle of the source relative to the plane of the telescopes.