
Up: Multicolour deep CCD
From the CM diagrams in Figs. 13 (click here)-16 (click here), the following
inferences can be drawn:
- (i)
- The photoelectric data merge smoothly with the CCD
observations, indicating that there are no systematic differences in
the calibrations.
- (ii)
- In all the star clusters under discussion, an evolutionary
effect is clearly visible in the upper part of the cluster MS. In NGC
5662 and NGC 6087, a few proper motion cluster members have reached
the giant phase of stellar evolution.
- (iii)
- Well defined cluster main-sequences extending from
to +3.0 in NGC 4103; from
to +4 in NGC 5662 and
from
to +4 in NGC 6087 are clearly seen. Such a long
sequence is not present in NGC 3228 (Fig. 13 (click here)). In fact very few
cluster members seems to exist in the present sample of CCD data. It could
be due to the fact that imaged regions are located almost at the edge of
the cluster diameter (see Table 4 (click here)).
- (iv)
- It is clear that below
, the luminosity
functions of the clusters do not rise steeply enough to dominate the
field star contamination. In this region, the present observations are
unable to separate unambiguously cluster members from the field stars.
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