Our determination for the cluster distance and reddening confirm earlier studies. From the small dispersion around the cluster main sequence in Fig. 3 we may conclude that most of the stars in Fig. 1 and Table 2 are physical members of NGC 6604. From the spatial concentration of early spectral types in Table 3, the diameter of NGC 6604 is of the order of 10 arcmin. The reddening follows the standard RV = 3.1 reddening law, with no evidence for a marked differential reddening over this cluster. The cluster age is estimated as 5 106 years. Our observations do not go faint enough to address the reality of the pre-ZAMS objects suspected by FD. Extrapolating from the turn-on tracks by Stauffer et al. (2000), pre-ZAMS objects in NGC 6604 should have 16, corresponding to a ZAMS spectral type somewhat later than A0. Thus, star #14 (which is 2 mag off the ZAMS) looks too bright both for a pre-ZAMS object and for an equal-mass binary, and therefore it should be a field star.
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