1. Finnish Centre for Astronomy with ESO (FINCA), Quantum, University of Turku, FI-20014, Turku, Finland
2. Armagh Observatory and Planetarium, College Hill, Armagh, Northern Ireland, BT61 9DG, UK
3. South African Astronomical Observatory, PO Box 9, Observatory, 7935 Cape Town, South Africa
4. Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, UK