the projection lens pl by an actuator system since the plate 12 is stationary there is no disturbance of the liquid 11 and hence no force transference to the projection system pl the actuator system for maintaining the plate 12 stationary comprises actuators 13 which are controlled in a feedback loop in response to the position of the plate 12 as measured by position sensor 14 mounted on the reference frame rf and or in a feed forward loop based on positioning instructions sent to the second positioning means pw the control system for the actuator system can implement anti noise measures interferometers capacitive sensors and encoders may be used as the position sensors and lorentz motors or voice coil motors as the actuators the use of actuators rather than a stiff connection to the bath in which the substrate table wt is immersed can facilitate easy removal of the substrates from the substrate table wt after imaging without unduly increasing the volume of liquid in the bath it will be appreciated that the force f d exerted on the plate 12 is not necessarily parallel to or linearly related to the motion v of the substrate table wt because of turbulence and delays in the transmission of force through the liquid 10 this may limit the usefulness of feed forward control nevertheless it is important that the force f a exerted on the plate 12 counters the force f d transmitted through the liquid 10 sufficiently that disturbances in the liquid 11 are kept low enough that the forces transferred to the projection lens are within acceptable limits it should be noted that in some circumstances.