The environment of 3C 255.

Very deep images of the field of the radio galaxy 3C 255 at z = 1.355 show that the object is in a region where there is an overdensity of objects with 22.5 <= R <= 24. Extending the number galaxy counts - magnitude relation up to R = 27, we find that there is no clear density excess around 3C 255 at fainter magnitudes. The radio source may be in a compact group or seen through foreground blue objects. In this 62" x 62" field, the mean distance to the nearest object at magnitude 25.4 <= R <= 27 is 2.6" only. The spatial distribution of faint objects suggests to search for filamentary structure or clumpiness on a larger field.