The present invention relates to a projectile seeker which comprises: (a) A hollow in the projectile for accommodating a light sensor; (b) A light sensor located within said hollow for sensing light which is emitted or reflected from a target, and for producing an electronic signal upon sensing such emitted light; and (c) A longitudinal shaped opening at the slanted front-side surface of the projectile for enabling a shaped field of view to said light sensor which is limited by the boundaries of said opening, the opening width varies in a direction from the front to the back of the projectile in order to cause said electronic signal to depend on the spinning of the projectile and to be proportional to the orientation of the projectile with respect to the object.