National Solar Observatory, Tucson, AZ, USA J. Leibacher Kayser-Threde GmbH, München, Germany M. Leipold Observatoire de Paris-Meudon, Meudon, France M. Maksimovic Instituto de Astrofísica de Canarias, La Laguna, Spain V. Martinez-Pillet California Institute of Technology, Pasadena, CA, USA...