This is a catalog of open cluster data, as compiled by Gosta Lynga, Lund Observatory. The aim of this catalog is to give salient data for all known open star clusters in our galaxy. As far as possible only published data values have been quoted; for some of the parameters, these values have been slected from references which can be obtained from the HEASARC. This data in part results from the merging of the data resulting from a joint project between K. Janes, C. Duke and Lynga, herein refered to as JDL data. The aim of that project was to discuss properties of the open cluster system by using existing data and by taking their accuracy into proper regard. Thus the data were assessed, mostly by Janes, weight assigned and weighted mean values derived of reddenings, turn-off colors and distances. This is a service provided by NASA HEASARC .