The research of P. Harmanec, including his trip to San Pedro Mártir Observatory, was supported by the research grant 205/96/0162 of the Granting Agency of the Czech Republic. He and P. Eenens are grateful to the Time Allocation Committee of the Observatorio Astronomico Nacional de Mexico for generous allocation of the observing time at San Pedro Mártir. We thank Drs. Elena Kazarovets and Nikolai Samus for very helpful comments. Finally, we acknowledge the use of the bibliographical service maintained at the Centre of Astronomical Data in Strasbourg.
© European Southern Observatory (ESO) 1999
Online publication: May 6, 1999