SIMBAD references

High accurate photometric data in the three filter, narrow-band Δa-system for five open clusters (NGC 2489, NGC 2567, NGC 2658, NGC 5281 and NGC 6208) are presented permitting one to detect apparent chemically peculiar stars. The ages and distances are wide spread to improve the statistics of peculiar stars in our Milky Way. A total of 235 stars within these clusters have been observed. We have detected ten apparent peculiar objects (six with significant positive and four with negative Δa-values) in four open clusters. Although three of them within the boundaries of NGC 2567 are probably not members of this cluster. Since no Stroemgren uvbyβ data are available from the literature, Johnson UBV photometry was used to test and calibrate our photometric data. The results from a comparison of both systems are excellent.