For twenty-five years the Institute of Astronomy of Lausanne University, Switzerland, which is a participating institute in the Strasbourg Data Centre, has been engaged in a long-term effort to collect published photoelectric photometric data in most existing systems. These collections certainly form the most complete photometric data bank ever realised. One of our main contributions concerns the homogeneization of stellar identifications. The data for the major systems (UBV, uvby, Geneva 7-colour) are available in Simbad, but no public and easy access has so far been provided for the wealth of existing photometric data.
The first database was coded by C. Nitschelm on a VAX computer and it has been described by Hauck et al. (1990). We have now completely rebuilt the database on Sun Sparc workstation under the /rdb package (Manis et al. 1988). In addition, we have updated all systems for which new data have been published before the end of 1995. The real new feature is the public access to the data collections, the Master Index, and the bibliographic references through the World Wide Web.
Among the numerous systems recognised, less than 20 are in fact used more or less regularly. If several systems with wide bands (UBV and RI systems) or intermediate-width bands (uvby, DDO for example) became very popular, many others, mostly with narrow or intermediate-width bands designed to measure specific features in the stellar energy distribution, were not used very much. Collecting data for such small systems may seem of purely historical interest, but owing to the numerous features observed and the sensitivity of the filters or colour indices to various astrophysical quantities, each system offers specific interests which may prove useful in particular applications if one knows about their existence. The proliferation of photometric system resulted also from the realisation of similar systems with nevertheless slightly different filters and standard stars.
Our long-term work aimed at providing valuable solutions to the main questions: (1) in which systems has any star been observed and (2) how to get the best values among those published.