Stromgren photometry of the open clusters NGC 6134 and NGC 3680

We present Stromgren photometry of the two southern open clusters NGC 6134 and NGC 3680, The field of NGC 6133 was observed with different shifts of the telescope and rotations of the CCD camera in order to detect and remove any large scale flat field errors using the technique described by Andersen et al. (1995). By using calibrations of the Stromgren indices we find the metallicity and interstellar reddening of the clusters: For NGC 6134 the results are [Fe/H] = 0.28 +/- 0.02 and E(b - y) = 0.263 +/- 0.004 and for NGC 3680 we find [Fe/H] = 0.09 +/- 0.02 and E(b - y) = 0.048 +/- 0.011. When comparing the observed colour-magnitude diagrams theoretical isochrones are find that models which include overshooting in the convective cores agree with the extended hook after the turnoff. From the isochrone fit we find ages of 0.69 +/- 0.10 Gyr and 1.45 +/- 0.15 Gyr for NGC 6134 and NGC 3680 respectively. Stromgren photometry of six known delta Scuti stars in NGC 6134 is presented.