Using the large size CCD images taken in B and V bands with a seeing of one arcsec, we have done stellar photometry of 18 dwarf galaxies situated in the Canes Venatici cloud direction. Most of them were resolved into stars for the first time. We determined the galaxy distances, using their brightest blue stars as a distance indicator. In spite of their low radial velocities, V0 < 500 km/s, some galaxies (UGC 6782, UGC 7131 and, probably, K 215), have distances around 15 Mpc. Located on the southern edge of the CVn cloud they may actually belong to the outskirts of the Virgo cluster.
For two LSB galaxies, K 200 and K 215, their distances may be overestimated, probably because of a lack of young massive stars. For the remaining objects the distance estimates range from 2.3 to 8.0 Mpc, which indicates their membership in the CVn cloud. The ratio of the median radial velocity, V0 = +304 km/s, to the median distance, D = 4.3 Mpc, leads to a local value of the Hubble parameter, H = 71 (km/s)/Mpc. This is larger than the cosmological value, because of the local peculiar velocity field. As the CVn cloud is only about 25 degrees from the direction of Virgo, a rough correction may be obtained from Eq. (5) in Teerikorpi et al. (1992), with = 2, = 20 Mpc, = 200 km/s. This gives H0 = 61 km/s/Mpc.
All the considered CVn cloud members are dwarf irregular galaxies with a typical colour = +0.32. Some of them (UGC 7605, UGC 7639, UGC 8638, and UGC 8833) show a systematic increase of the colour outwards from their centre. Like other nearby galaxies: NGC 1705, NGC 2915 (Mackie & Meurer 1992), and UGC 1104 (Karachentsev et al. 1996), these objects belong, probably, to a particular kind of dwarfs, which have an underlying low surface brightness old disk with a superimposed central star-forming region.
Among the studied objects, there is an intrinsically faint ( ) and low surface brigthess galaxy, UGCA 292, with an unusually blue integrated colour, = +0.08. According to the HI data by Lo et al. (1993), it has also an unusually high HI mass-to-luminosity ratio, 6 . Because the fraction of its HI mass accounts for about 70% of the total mass, this very blue nearby dwarf galaxy may be considered as one of the youngest known objects in the Local Universe.
We have to note finally that some of the galaxies (UGC 8638, UGC 8651 and UGC 8833) should be observed again with a higher resolution to improve their distance estimates.
The authors thank S.S. Kajsin for his participation in the data processing. This work is partially supported by a INTAS-RFBR grant No. 95-IN-RU-1390.