ESA/HST and ESO archive access and visualisation in the VO era

Turning the ESA Hubble Space Telescope Archive along with ESO Archive Facility into a VO-compliant data centre is a complex process: new technologies and standards have to be adopted and a more detailed description (metadata) of the data holdings is required. While Astrovirtel helped us understanding and exploring ways to achieve the latter, the current world-wide effort of developing VO-compliant software can allow us to provide with limited in-house effort the aforementioned metadata through a modern VO interface. This technology has proved to be mature enough to be used in the presented example, where HST-ACS & HST-WFPC2 associations (a ST-ECF, CADC, STScI project) metadata and field of view are visualised with Aladin. This is not only a useful application for the end user but also a first step of the on-going effort toward a VO-compliant Archive. In spite of its novelty and being still under development, VO technology is mature to cope with real life scenarios, allowing the implementation of powerful concepts like the metadata tree presented in our example