TOPBASE AT THE CDS

TOPbase, the Opacity Project atomic database, has been set up at the C entre de Donnees Astronomiques de Strasbourg (CDS), France, for genera l access via Internet. This database contains accurately calculated en ergy levels, f-values and photoionisation cross sections for astrophys ically abundant ions. We briefly describe the physical model and compu tational method used, the atomic data specifications, the database man agement system and the network access arrangements. The new facility s hould be of value to the astronomical community.