An appliance for moiré measurement of an object (12) includes a grating arrangement having a first grating (11) positioned upstream of the object and including test structures to be imaged, a second grating (14) positioned downstream of the object, and an evaluation unit having at least one detector evaluating moiré structures produced by superposing the two gratings in a detection plane situated downstream of the second grating. The object is an anamorphic imaging system, and the respective grating periods of the first grating and of the second grating are selected so that the grating period of the second grating corresponds to a common multiple or a common divisor of the respective periods of two test structure images of the test structures of the first grating produced by the imaging system in two different measurement positions. The two measurement positions differ in relative grating arrangement position and test object position.