  We present stellar photometry in the UBV passbands for the globular cluster
M5 = NGC5904. The observations, short-exposured photographic plates and CCD
frames, were obtained in the RC-focus of the 2m telescope of the Natl. Astron.
Obs. 'Rozhen'. All stars in an annulus with radius 1 < r < 5.5 arcmin were
measured. We show that the UV CMDs describe different evolutionary stages in a
better manner than the 'classical' (V, B-V) diagram. We use HB stars, with
known spectroscopic Teff, to check the validity of the colour zero-point. A
review of all known UV-bright star candidates in M5 is made and some of their
parameters are catalogued. Six new stars of this kind are suspected on the
basis of their position on the CMD. New assessment of the cluster reddening and
metallicity is done using the (U-B, B-V) diagram. We find [Fe/H]= -1.38, which
confirms the Zinn & West (1984) value contrasting with recent spectroscopic
estimates. In an effort to clarify the question of the gap in the BHB stellar
distribution and to investigate some other peculiarities, we use the relatively
long-base colour index U-V. A comparison of the unreddened (V, U-V)
distribution of HB stars with a canonical ZAHB model (Dorman et al. 1993)
reveals that the hottest stars rise above the model line. We find this similar
to the 'u-jump' found in the Stroemgren photometry (Grundahl et al. 1998,
1999). (U-B)o indeces of 18 BHB stars with (B-V)o in [-0.02, 0.18] were used to
estimate their ultraviolet deficiency. It is shown that low gravity log g < 2
Kurucz's atmospheric models fit well the observed distribution of these stars
along the two-colour diagram.
