Abstract: A lithographic device comprising a mask table (5), a projection system (3), a substrate table (1) which is displaceable relative to the projection system (3) by means of a drive unit (21), and a measuring system (39) for measuring a position of the substrate table (1) relative to the projection system (3). A stationary part (157) of the drive unit (21) is fastened to a machine frame (85) of the lithographic device, while a stationary part (51, 53, 55) of the measuring system (39) is fastened to a reference frame (89) of the lithographic device which is dynamically isolated from the machine frame (85) by means of dynamic isolators (95). This prevents vibrations caused in the machine frame (85) by reaction forces of the drive unit (21) from being transmitted to the reference frame (89), so that the accuracy of the measuring system (39) is not adversely affected by such vibrations.

Abstract: A positioning device (21, 31) with a drive unit (147, 149, 151; 69, 71) with which an object table (1, 5) is displaceable over a guide (141, 65) which is fastened to a frame (45) of the positioning device (21, 31). The positioning device (21, 31) includes a force actuator system (205) which exerts on the frame (45) a compensation force which has a moment about a reference point (P) of the frame (45) whose value is equal to a value of a moment of a force of gravity acting on the object table (1, 5) about the reference point (P), and whose direction is opposed to a direction of the moment of said force of gravity. The use of the force actuator system (205) prevents the frame (45) from vibrating or being elastically deformed when a point of application on the frame (45) of the force of gravity is displaced relative to the frame (45) during a displacement of the object table (1,5).