Target object used for retroflexion of optical radiation

A target object for retroreflection of optical radiation, comprising:

• at least six triple prisms of the same type which are combined in an annular manner to form an all-round reflector, which all-round reflector is capable of being arranged on a geodetic plumbing staff, wherein:
• the centre of the ring formed by the triple prisms forming the optical centre of the all-round reflector;
• the triple prisms are in the form of triple prisms having in each case a triangular light entry surface;
• successive, adjacent triple prisms being rotated through 180° relative to one another, with in each case directly touching lateral surfaces;
• and
• the arrangement of the triple prisms is such that a clearance for receiving a part of the plumbing staff is present in the centre of the ring, in that the virtual images of the triple prism tips lie in each case substantially in a plane which is perpendicular to a reference axis passing through the centre of the ring and running parallel to the longitudinal extension of the plumbing staff.