Preparation of detailed night schedule prior to an observing run can be tedious, especially for solar system objects which coordinates are epoch-dependent. We aim at providing the community with a Web service compliant with Virtual Observatory (VO) standards, to create tables of observing conditions, together with airmass and sky charts, for an arbitrary list of targets. We take advantage of available VO services such as the SIMBAD astronomical database, the Aladin sky atlas, and the Miriade ephemerides generator to build a new service dedicated to the planning of observations. The requests for ephemerides charts and tables are handled by a VO-compliant Web service. For each date, and each target, coordinates in local and equatorial frames are computed, and used to select targets accordingly to user's criteria for visibility. This new service, dubbed ViSiON for Visibility Service for Observing Night, is a new method of Miriade Web service hosted at IMCCE. It allows anyone to create graphics of observing conditions and tables summarizing them, provided as PDF, VOTable, and xHTML documents.