New infrared photometry of a sample of 39 stars in the open cluster NGC 752 is presented. These observations confirm the bimodality of the main sequence previously reported. The nature of this behavior is analyzed on the basis of the binary hypothesis.

Preliminary results on new CCD photometry inV andB bands of approximately 5000 stars in four overlapping fields in the globular cluster M3 are presented. The colour-magnitude diagram shows a very well-defined sequence with a small scatter, going fainter than previously published work on this cluster. The turn-off point found atV=19.1±0.2 mag and (B

Not Available

Not Available

We present preliminary results of CCD BV photometry of the old open cluster King 2. The values obtained for the main parameters are:E(B-V)=0.31, (m-M)0=13.78, metal content approximately solar, and age 6×109 yr. From the comparison with synthetic colour-mgnitude diagrams generated by models with overshoot we try to answer the question whether or

The usually assumed identification of small-scale magnetic concentrations with bright facular or network points on the photosphere is observationally checked by using high spatial resolution spectra of Ca II K bright points very near the disk center. The detection of spatially unresolved magnetic structures is made via a new differential analysis