Affiliation: | Department of Pure and Applied Physics, The Queen's University of Belfast, Belfast BT7 1NN;South African Astronomical Observatory, PO Box 9, Observatory 7935, Cape, South Africa;European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago 19, Chile;Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ |