Sydney University Stellar Interferometer
Coordinates: 30°19′20″S 149°32′54″E / 30.32222°S 149.54833°E
The Sydney University Stellar Interferometer (SUSI) is an optical long baseline interferometer owned by The University of Sydney. It is located in the Paul Wild Observatory, 20 km west of Narrabri town in New South Wales, Australia. The interferometer has several siderostats, which collect and reflect starlight into the optical laboratory for interferometry via two vacuum pipes. Although mirrors at the siderostats are 20 cm in diameter, the effective aperture size is 14 cm as they are operated at angles of about 45°. By selecting the different siderostats at different distances the baseline of the interferometer can be varied from 5m and 640m. Since not all the siderostat stations are equipped with mirrors at present, the maximum usable baseline of the interferometer is 160m. With beam combining instruments that operate at visible wavelengths (~550-850 nm), SUSI has angular resolution of up to ~0.7mas (milliarcseconds).