ANGULAR POINTING AND GUIDANCE FOR THE SYDNEY-UNIVERSITY STELLAR INTERFEROMETER

The Sydney University Stellar Interferometer (SUSI) uses siderostats ( plane, alt-azimuth mounted mirrors) to reflect starlight into the inst rument. The analysis of the pointing and guidance of the siderostats b y traditional methods is not practical and vector algebra has been use d to develop the required algorithms. Real siderostats will not be ide al and can be modelled by a set of parameters. The methods for determi ning the model parameters and for incorporating them into the guidance and pointing algorithms are described. Field rotation also affects th e operation of SUSI, and the field rotation angle and related quantiti es are also determined.