EUV reflectometer (100, 300) for measuring the reflectivity of a test object having a reflective effect for EUV radiation, depending on the wavelength of the EUV radiation and on the angle of incidence of the EUV radiation on a reflective surface of the test object, comprising: an EUV radiation source for emitting EUV radiation; a beam shaping unit for receiving EUV radiation from the EUV radiation source and for generating a measurement beam; a positioning device for holding the test object and for positioning the test object in relation to the measurement beam in a plurality of degrees of freedom in such a way that, during operation, the measurement beam impinges on the reflective surface at a predefinable measurement location in the region of a measurement spot at a predefinable angle of incidence, a detector that is sensitive to EUV radiation, for detecting the EUV radiation reflected by the reflective surface, characterized in that (a)the positioning device has a main carrier, which is rotatable about a vertical rotation axis by means of a rotary drive and on which a parallel kinematic multi-axis system having a multiplicity of actuators is arranged, which act on a common platform, which is movable in three linear and three rotational degrees of freedom in space by means of the actuators, the platform carrying a holding device for holding the test object and a rotary drive for rotating the holding device about a rotation axis, and (b)the positioning device is assigned a measuring system (600, 700, 1000) for determining the location and position of the test object in space and/or in relation to the measurement beam, said measuring system being independent of drives of the actuators. an EUV radiation source for emitting EUV radiation; a beam shaping unit for receiving EUV radiation from the EUV radiation source and for generating a measurement beam; a positioning device for holding the test object and for positioning the test object in relation to the measurement beam in a plurality of degrees of freedom in such a way that, during operation, the measurement beam impinges on the reflective surface at a predefinable measurement location in the region of a measurement spot at a predefinable angle of incidence, a detector that is sensitive to EUV radiation, for detecting the EUV radiation reflected by the reflective surface, characterized in that (a)the positioning device has a main carrier, which is rotatable about a vertical rotation axis by means of a rotary drive and on which a parallel kinematic multi-axis system having a multiplicity of actuators is arranged, which act on a common platform, which is movable in three linear and three rotational degrees of freedom in space by means of the actuators, the platform carrying a holding device for holding the test object and a rotary drive for rotating the holding device about a rotation axis, and (b)the positioning device is assigned a measuring system (600, 700, 1000) for determining the location and position of the test object in space and/or in relation to the measurement beam, said measuring system being independent of drives of the actuators. (a)the positioning device has a main carrier, which is rotatable about a vertical rotation axis by means of a rotary drive and on which a parallel kinematic multi-axis system having a multiplicity of actuators is arranged, which act on a common platform, which is movable in three linear and three rotational degrees of freedom in space by means of the actuators, the platform carrying a holding device for holding the test object and a rotary drive for rotating the holding device about a rotation axis, and (b)the positioning device is assigned a measuring system (600, 700, 1000) for determining the location and position of the test object in space and/or in relation to the measurement beam, said measuring system being independent of drives of the actuators.