The Work on Cross-Reference Tables

The problem

A large fraction of open clusters have been studied by several authors who have created personal numbering systems. The intersections between these different studies are often partial because photometric studies go to fainter magnitudes in smaller areas, while proper motion studies are concernerd with stars of brighter limiting magnitudes, but over a much wider field.

This situation creates a serious problem to work efficiently with star cluster observations, because one usually needs to know the various numbers attributed to each star in a cluster. This is also a major concern for the development of the database.

The solution

Since 1972, a big effort has been undertaken to provide a solution to this problem. A convenient numbering system has been adopted for each cluster and cross-identifications between numbering systems in many clusters have been determined. These cross-identifications have been stored in tables (Mermilliod J.-C. 1979, A&AS 36, 163). Their structure should be obvious: the first column contains the adopted numbering system, and the subsequent columns contain the corresponding numbers attributed by the various authors.

As general rule, the adopted numbering system is similar to the one given in the first reference. It has often been extended to include additional stars coming from the other studies.

Access to the tables

The present Web page offers a possibility to display the existing tables and search them directly for specific star numbers in any of the listed references.

The sort on columns labelled 13 or 14 does presently not work when the numbering system is complex, like 22 - 75.

Look at the help page to see how to use it.
Last update: 10 December 1997