The Hamburg/RASS Catalogue of Optical Identifications of ROSAT Bright Source X-Ray Sources

We used digitized Schmidt direct and prism plates taken for the northern hemisphere Hamburg Quasar Survey (HQS) to obtain optical identifications for all high galactic latitude X-ray sources in the ROSAT Bright Source Catalogue (RASS-BSC) at \b\ greater than or equal to 30 deg and delta greater than or equal to 0 deg. In this part of the sky the RASS-BSC contains 5341 X-ray sources. We found 51% extragalactic counterparts (AGN, galaxies, clusters of galaxies), and 31% stellar sources. 3% are empty fields and for further 15% no unique identification could be given. The digitized database of Schmidt plates and tools to use this database for identification work will be implemented in the German Virtual Observatory (GAVO).