New optical fields and candidates of 10 3C radio sources. I. The R-band images

Using new R-band images acquired as part of the 3CR Snapshot Survey with the Wide Field Planetary Camera 2 on the Hubble Space Telescope, we present positive optical identifications of three previously unidentified 3C radio sources (3C 91, 134, and 141). The fields of five others (3C 131, 152, 399.1, 415.2, and 468.1) are also presented with tentative identifications for some. The fields of two other sources (3C 249 and 3C 250) are empty. Eight sources lie along the Galactic plane (\b\ < 10 degrees) and are consequently heavily obscured, while the two empty fields are located at higher Galactic latitudes. Observed and corrected R magnitudes of each candidate are calculated. Confirmation of the true optical counterpart will require deep near-IR imaging and long-slit spectroscopy to determine the nature and redshift of the counterparts and candidates.