USE OF PHOTOGRAPHIC PLATE ARCHIVES FOR STUDYING THE LONG-TERM BEHAVIOUR OF THE PLEIADES FLARE STARS

As a result of the cooperation between the Sofia Sky Archive Data Center (Bulgaria) and Bamberg Observatory (Germany), Royal Observatory of Edinburgh (UK), Konkoly Observatory (Hungary), Strasbourg Observatory, Institute of Astronomy in Cambridge (UK), etc., a programme for investigation of the long-term behaviour of the Pleiades active dwarf stars (in particular, flare stars) is in progress. Existing plates in the Pleiades are found in different European plate archives, made since the end of the nineteenth century, by the searching tool of the wide-field plate database (http://www.skyarchive.org), which provides detailed information for astronomical plate archives all over the world, as well as for plates themselves. We investigate the Pleiades flare stars (UV Cet-type stars) included in the flare Stars database and identified in the USNO A2.0 catalogue. 68 Pleiades plates are already digitized with different scanning machines such as PDS 1010 (Sofia), PDS 2020 (Munster), SUPER COSMOS (Edinburgh), APM (C...