1. South African Astronomical Observatory, Observatory Road, Observatory, 7925 Cape Town, RSA
2. Department of Physics & Astronomy, University of Southampton, Southampton SO17 1BJ, UK
3. Department of Physics, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa
4. Institut d’Astrophysique de Paris, CNRS et Sorbonne Université, UMR 7095, 98bis Bd Arago, F-75014 Paris, France
5. Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, PL-00-716 Warsaw, Poland
6. Department of Physics, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa
7. Center for Astrophysics, Harvard-Smithsonian, 60 Garden St, Cambridge, MA 02138, USA
8. Inter-University Centre for Astronomy and Astrophysics, Pune, Maharashtra 411007, India