The main body of this work has been carried out at Armagh Observatory, supported by PPARC grant GR/K04613. We also acknowledge support at Armagh in terms of both software and hardware by the STARLINK Project, funded by the UK PPARC. The WHT is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias.
© European Southern Observatory (ESO) 1998
Online publication: July 20, 1998