1. Université de Strasbourg, CNRS, Observatoire astronomique de Strasbourg , UMR 7550, F-67000 Strasbourg, France
2. Department of Physics and Astronomy, University of Victoria , Victoria, BC V8P 5C2, Canada
3. Dipartimento di Fisica e Astrofisica, Univerisità degli Studi di Firenze , via G. Sansone 1, I-50019 Sesto Fiorentino, Italy
4. INAF/Osservatorio Astrofisico di Arcetri , Largo E. Fermi 5, I-50125 Firenze, Italy
5. GEPI, Observatoire de Paris, Université PSL , CNRS, 5 Place Jules Janssen, F-92195 Meudon, France
6. Instituto de Astrofísica de Canarias , E-38205 La Laguna, Tenerife, Spain
7. Dpto. Astrofísica, Universidad de La Laguna , E-38206 La Laguna, Tenerife, Spain
8. Max-Planck-Institut für Astronomie , Königstuhl 17, D-69117 Heidelberg, Germany
9. UK Astronomy Technology Centre, Royal Observatory , Blackford Hill, Edinburgh EH9 3HJ, UK
10. Kapteyn Astronomical Institute, University of Groningen , Landleven 12, NL-9747 AD Groningen, the Netherlands