CCD STROMGREN UVBY PHOTOMETRY OF THE YOUNG CLUSTERS NGC-1893, NGC-457, BERKELEY-94 AND BOCHUM-1

Stromgren uvby colours are presented for 150 stars in fields containing the young galactic clusters NGC 1893, NGC 457, Berkeley 94 and Bochum 1. Cluster members are identified via inspection of colour magnitude diagrams and reddening-free indices, and intrinsic colours are calculated. Members of Be94 exhibit a substantial spread of reddenings, which because of the compactness of this cluster may be due to circumstellar material. A blue straggler is identified in NGC 457. Assuming a standard galactic reddening law, the distances to the clusters are 4.8 kpc for NGC 1893, 2.5 kpc for NGC 457, 3.5 kpc for Be 94 and 4.8 kpc for Bo 1.