In astronomy, axial tilt is the angle between an object's rotational axis, and a line perpendicular to its orbital plane. Do not confuse this with inclination.To measure obliquity, use the Right hand grip rule for both the rotation and the orbital motion, i.e.: the line from the vertex at the object's centre to its north pole (above which the object appears to rotate counter-clockwise); and the line drawn from the vertex in the direction of the normal to its orbital plane, (above which the object moves counter-clockwise in its orbit). At zero degrees, these lines point in the same direction.Planet Venus has an axial tilt of 177.3 degrees because it is rotating in retrograde direction, opposite to other planets like Earth. North pole of Venus is pointed 'downward'(our southward). Planet Uranus is rotating on its side in such a way that its rotational axis and hence its north pole is pointed almost in the same direction of its orbit around the Sun. Hence axial tilt of Planet Uranusis 97 degrees.