1995A&A...294..648H

We present Stroemgren CCD photometry for the globular clusters NGC 1866 and NGC 330 in the LMC/SMC and for their neighbouring field population. The metallicities, which result from the Stroemgren data for NGC 1866 and NGC 330 are -0.43±0.18dex and -0.93±0.16dex, respectively. The metallicity of NGC 1866 could be lower by 0.2dex, if NGC 330 has an abundance of -1.1dex, as it is indicated by spectroscopic studies. This is the first direct determination of the metallicity of NGC 1866, a key object in stellar evolution theory. Additionally, we determine metallicities of (older) field stars in the cluster region and use them to estimate ages for a number of individual red giants by comparison with theoretical isochrones. For a number of reasons, these results are preliminary. However, several interesting features appear which are worth to be studied with improved accuracy: in the field of NGC 330, no clear age-metallicity relation can be seen. Some field stars seem to be older than NGC 121, the oldest SMC globular cluster. In the field of 1866, there are some stars falling in the age range between 3 and 10Gyr, where star clusters are lacking. A very small age-metallicity relation appears, but the existence of stars with metallicities lower than -1.5dex is not certain even among the oldest stars.