The 6C survey of radio sources - III. The zone 48<Dec<68, 05h25<RA<18h17

The 6th Cambridge survey of radio sources covers most of the sky north of δ+30° with an angular resolution of 4.2 × 4.2 cosec δ arcmin² and reaches a limiting flux density of 160 mJy at 151 MHz in the present zone, with completeness achieved at 600 mJy. This paper presents 188 pages of maps of a region 48°<δ<68°, 05^h25^m<α<18_sun17^m, together with a list of 8749 sources in the 1950 degree² covered. The text outlines only essential details of operation and analysis specific to this zone, since the principles of the method used to gather data and produce maps from a non-tracking telescope operating at declinations other than the north celestial pole are fully described in Paper II of this series. The coverage of the present paper overlaps that of Paper II for the range 48°<δ<51°, 08^h 30^m < α < 17^h 30^m .