  In a sample of six young open clusters we investigated 1753 objects using the
narrow band, three filter Delta a photometric system resulting in the detection
of eleven bona-fide magnetic chemically peculiar (CP) stars and five Be or
metal-weak stars. The results for the distant cluster NGC 3105 is most
important because of the still unknown influence of the global metallicity
gradient of the Milky Way. These findings confirm that CP stars are present in
open clusters of very young ages (log t > 6.90) at galactocentric distances up
to 11.4 kpc. For all programme clusters the age, reddening, and distance
modulus were derived using the corresponding isochrones. Some additional
variable stars within Stock 16 could be identified by comparing different
photometric studies.
