1. Armagh Observatory and Planetarium, College Hill, Armagh BT61 9DG, UK
2. School of Physics, Trinity College Dublin, College Green, Dublin 2, Ireland
3. Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA, UK
4. South African Astronomical Observatory, PO Box 9, Observatory, 7935, South Africa
5. Southern African Large Telescope Foundation, PO Box 9, Observatory, 7935, South Africa