Most of this research has been done under supervision by Dr. P.B. Byrne at Armagh Observatory. His untimely death occurred before this work was completed. It has been a sad end for a project that benefited so much from his enormous help and encouragement. Research at Armagh Observatory is grant-aided by the Dept. of Education for Northern Ireland. Support staff of the WHT (La Palma) is gratefully acknowledged for their assistance during the observations. This work has also benefited from the STARLINK project funded by the UK PPARC. The author acknowledges a PPARC Research Studentship No. 9400747X during the period of this work. The author would like to thank all the staff in LAEFF for their kind support during the last steps of this work, particularly Dr. B. Montesinos for his help and careful reading of the manuscript. The author also wishes to thank the referee of this paper, Dr. A. Collier-Cameron, for helpful comments.
© European Southern Observatory (ESO) 1998
Online publication: August 27, 1998